A128099 → Veronese 2

nonnegative coefficients

Proved for all n: all roots real, in (−∞, 0] · coefficients of one sign · interlacing (weak) · Hadamard kernel what this means

Recurrence

\(P_{n}(x) = \left(2\right)\,P_{n-1}(x) + \left(-1\right)\,P_{n-2}(x) + \left(4\,x\right)\,P_{n-4}(x)\)

\(P_{0}(x) = 1\)

\(P_{1}(x) = 1\)

\(P_{2}(x) = 1\)

\(P_{3}(x) = 1\)

Rows ?

n	x⁰	x¹	x²	x³	P_n(1)
0	1				1
1	1				1
2	1				1
3	1				1
4	1	4			5
5	1	12			13
6	1	24			25
7	1	40			41
8	1	60	16		77
9	1	84	80		165
10	1	112	240		353
11	1	144	560		705
12	1	180	1120	64	1365
13	1	220	2016	448	2685
14	1	264	3360	1792	5417

Computed in your browser ?

Technical details

Node id: n-77e2730562eef718 · revision 1 · JSON
Definition source: derived:veronese_section_2_0
Fingerprint: f6-1b7c3c25e5605b3d

Observed on the stored rows ?

Degrees: 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3 (irregular)
Palindromic rows: no
γ-positive (gamma_positive): no
Nonnegative coefficients (nonn): yes
Only rational roots (rr_by_factors: every nonzero row is a product of linear factors over ℚ): no

OEIS matches ?

No OEIS matches.

OEIS submission text ?

Fields to paste into an OEIS submission: the example %e, the formula %F and programs %t (Mathematica) and %o (PARI/GP) that list the same rows. For an OEIS link the row numbers, the offset and the orientation are those of the entry, as matched; the matched terms were compared with the published ones, which identifies the node with the entry on a finite prefix, not for every n. The PARI/GP program is not machine-checked here.

The atlas's own rows: n = 0, …, ascending powers of x

%e Example

Triangle begins:
  0: 1;
  1: 1;
  2: 1;
  3: 1;
  4: 1,  4;
  5: 1, 12;
  6: 1, 24;
  7: 1, 40;
  8: 1, 60, 16;
  9: 1, 84, 80;

%F Formula

The row polynomials satisfy P(n,x) = 2*P(n-1,x) - P(n-2,x) + 4*x*P(n-4,x) for n >= 4, with P(0,x) = 1, P(1,x) = 1, P(2,x) = 1, P(3,x) = 1.

%t Mathematica

P[0, x_] := 1;
P[1, x_] := 1;
P[2, x_] := 1;
P[3, x_] := 1;
P[n_, x_] := P[n, x] = Expand[2*P[n - 1, x] - P[n - 2, x] + 4*x*P[n - 4, x]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten

%o PARI/GP

P(N) = {my(v = vector(N + 1)); v[1] = 1; v[2] = 1; v[3] = 1; v[4] = 1; for(n = 4, N, my(i = n + 1); v[i] = 2*v[i - 1] - v[i - 2] + 4*x*v[i - 4]); v};
row(n, p) = {my(c = Vecrev(p)); c};
T(N) = {my(v = P(N)); concat(vector(#v, i, row(i - 1, v[i])))};
T(9)

Generated with polytool c48629374597.

Proved properties

Real-rooted. Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 0]
Every polynomial of the sequence has only real roots, inside the stated interval.

by the cited steps: e-85dbfca73c9c3bb9
Coefficients of one sign. Every nonzero row, n >= 0: the coefficients of P_n have one sign
All coefficients of each polynomial have the same sign (after x -> -x when alternating).

derived from the cited steps by a stated theorem: e-85dbfca73c9c3bb9
Hadamard kernel (Malo). Rows P_n, n >= 0, are Hadamard kernels (preserve real-rootedness)
Multiplying the coefficients of any real-rooted polynomial termwise by those of a row (Hadamard product) gives a real-rooted polynomial again.

derived from the cited steps by a stated theorem: e-85dbfca73c9c3bb9
Interlacing of consecutive rows. Rows P_(m-1), P_m interlace (weak, previous interlaces next) for every m >= 1
The roots of consecutive polynomials alternate on the real line.

by the cited steps: e-85dbfca73c9c3bb9

Proof chains

1 incoming proof step. Each step is expanded back to the roots of the proof DAG, the theorem checks of a node's own rule. JSON

veronese_section r=2, j=0, shift 0 e-85dbfca73c9c3bb9

Veronese sections of Pólya frequency sequences [ASW52; Edr53; AW24] polytool ?
- premise (sequence): Triangle read by rows: T(n,k) is the number of ways to tile a 3 X n rectangle with k pieces of 2 X 2 tiles and 3n-4k pi…
  uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 0]
  - gamma_polynomial scale 1, shift 0 e-250eeed7ad07d148
    
    Gamma criterion RealRooted IsGammaExpansion.isRealRooted_and_hasRootsNonpos_iff ?
    
    premise (sequence): Pascal-(1,2,1) array read by antidiagonals.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 0]
    
    theorem_check liu_wang_derivative_lag e-1f8dc4b132ba6116 root: theorem check
    
    Liu–Wang theorem with a lag row [LW07, Thm 2.1] RealRooted ?
    
    preserver_image reversal, shift 0 e-8efc9aafb30c2198
    
    Affine, reversal and Möbius substitutions (elementary) polytool ?
    
    premise (sequence): Pascal-(1,2,1) array read by antidiagonals.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 0]
    
    ↵ theorem_check liu_wang_derivative_lag e-1f8dc4b132ba6116 (expanded above)
  - preserver_image reversal, shift 0 e-6b9d711da9b2e815
    
    Affine, reversal and Möbius substitutions (elementary) polytool ?
    
    premise (sequence): A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 0]
    
    basis_map A027467 e-0db30c1d149f8e9a
    
    Geometric basis map (elementary) polytool ?
    
    premise (sequence): basis-map coefficients of A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 15]
    
    preserver_image affine, shift 0 e-0ffa0091fcab81ab
    
    Affine, reversal and Möbius substitutions (elementary) polytool ?
    
    premise (sequence): A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-8, 0]
    
    theorem_check ma_wang_interval e-2d5b16bf2955a407 root: theorem check
    
    Ma–Wang interval theorem [MW08, Thm 2, Cor 3] RealRooted RealRooted.affineEndpointStep_closed ?
    
    basis_map A038303 e-1078e1fe9c978d23
    
    Geometric basis map (elementary) polytool ?
    
    premise (sequence): basis-map coefficients of A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 10]
    
    preserver_image affine, shift 0 e-ba5819a43d999a58
    
    Affine, reversal and Möbius substitutions (elementary) polytool ?
    
    premise (sequence): A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-8, 0]
    
    ↵ theorem_check ma_wang_interval e-2d5b16bf2955a407 (expanded above)
    
    basis_map A038327 e-39068ae2f1d878f6
    
    Geometric basis map (elementary) polytool ?
    
    premise (sequence): basis-map coefficients of A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 12]
    
    preserver_image affine, shift 0 e-0ef3f7736abad08b
    
    Affine, reversal and Möbius substitutions (elementary) polytool ?
    
    premise (sequence): A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-8, 0]
    
    ↵ theorem_check ma_wang_interval e-2d5b16bf2955a407 (expanded above)
    
    preserver_image reversal, shift 0 e-5066005127b21217
    
    Affine, reversal and Möbius substitutions (elementary) polytool ?
    
    premise (sequence): Triangle read by rows: T(n,k) is the number of ways to tile a 3 X n rectangle with k pieces of 2 X 2 tiles and 3n-4k pi…
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 0]
    
    ↵ gamma_polynomial scale 1, shift 0 e-250eeed7ad07d148 (expanded above)
    
    parent_provers paper_theorem e-7c3667820056c57c root: theorem check
    
    Parent-row provers of polytool polytool ?
    
    basis_map A027465 e-76bf35985f9d5eb4
    
    Geometric basis map (elementary) polytool ?
    
    premise (sequence): basis-map coefficients of A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 3]
    
    preserver_image affine, shift 0 e-5f9e6216c74dfca3
    
    Affine, reversal and Möbius substitutions (elementary) polytool ?
    
    premise (sequence): A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-8, 0]
    
    ↵ theorem_check ma_wang_interval e-2d5b16bf2955a407 (expanded above)
    
    basis_map A038243 e-7b55c4767302dd2a
    
    Geometric basis map (elementary) polytool ?
    
    premise (sequence): basis-map coefficients of A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 5]
    
    preserver_image affine, shift 0 e-0c61b86c2e25257b
    
    Affine, reversal and Möbius substitutions (elementary) polytool ?
    
    premise (sequence): A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-8, 0]
    
    ↵ theorem_check ma_wang_interval e-2d5b16bf2955a407 (expanded above)
    
    basis_map A007318 e-89ed187733702f47
    
    Geometric basis map (elementary) polytool ?
    
    premise (sequence): basis-map coefficients of A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 1]
    
    preserver_image affine, shift 0 e-38de1ebb8f2e73b6
    
    Affine, reversal and Möbius substitutions (elementary) polytool ?
    
    premise (sequence): A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-8, 0]
    
    ↵ theorem_check ma_wang_interval e-2d5b16bf2955a407 (expanded above)
    
    basis_map A038255 e-9c1dd42dfa910ea7
    
    Geometric basis map (elementary) polytool ?
    
    premise (sequence): basis-map coefficients of A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 6]
    
    preserver_image affine, shift 0 e-4867241b67312c9e
    
    Affine, reversal and Möbius substitutions (elementary) polytool ?
    
    premise (sequence): A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-8, 0]
    
    ↵ theorem_check ma_wang_interval e-2d5b16bf2955a407 (expanded above)
    
    basis_map A038207 e-a0ae771232cbba16
    
    Geometric basis map (elementary) polytool ?
    
    premise (sequence): basis-map coefficients of A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 2]
    
    preserver_image affine, shift 0 e-c345fe1d5254381d
    
    Affine, reversal and Möbius substitutions (elementary) polytool ?
    
    premise (sequence): A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-8, 0]
    
    ↵ theorem_check ma_wang_interval e-2d5b16bf2955a407 (expanded above)
    
    basis_map A038291 e-a2d6a4286b164d3d
    
    Geometric basis map (elementary) polytool ?
    
    premise (sequence): basis-map coefficients of A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 9]
    
    preserver_image affine, shift 0 e-f1a9ca5f4baaa1dd
    
    Affine, reversal and Möbius substitutions (elementary) polytool ?
    
    premise (sequence): A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-8, 0]
    
    ↵ theorem_check ma_wang_interval e-2d5b16bf2955a407 (expanded above)
    
    basis_map A038231 e-b4c854eb781c5167
    
    Geometric basis map (elementary) polytool ?
    
    premise (sequence): basis-map coefficients of A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 4]
    
    preserver_image affine, shift 0 e-b26782bfa4993a06
    
    Affine, reversal and Möbius substitutions (elementary) polytool ?
    
    premise (sequence): A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-8, 0]
    
    ↵ theorem_check ma_wang_interval e-2d5b16bf2955a407 (expanded above)
    
    basis_map A038279 e-c41010d0d9363851
    
    Geometric basis map (elementary) polytool ?
    
    premise (sequence): basis-map coefficients of A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 8]
    
    preserver_image affine, shift 0 e-765910d978fe3ce9
    
    Affine, reversal and Möbius substitutions (elementary) polytool ?
    
    premise (sequence): A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-8, 0]
    
    ↵ theorem_check ma_wang_interval e-2d5b16bf2955a407 (expanded above)
    
    basis_map A027466 e-de853701eca80777
    
    Geometric basis map (elementary) polytool ?
    
    premise (sequence): basis-map coefficients of A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-inf, 7]
    
    preserver_image affine, shift 0 e-2f0380ac472e9edc
    
    Affine, reversal and Möbius substitutions (elementary) polytool ?
    
    premise (sequence): A Jacobsthal triangle.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in (-8, 0]
    
    ↵ theorem_check ma_wang_interval e-2d5b16bf2955a407 (expanded above)
    
    basis_map A113953 e-4e53ceff1d4735da
    
    Affine-current basis map theorem polytool RealRooted orderTwoConstants_nonneg_iff ?
    
    premise (sequence): a(n) = 1 if n is of the form m(m+3)/2, otherwise 0.
    uses: Every row P_n, n >= 0, is zero or real-rooted with all roots in [0, 0]
    
    no recorded property covers this requirement
    
    ↵ theorem_check ma_wang_interval e-2d5b16bf2955a407 (expanded above)
  - ↵ parent_provers paper_theorem e-7c3667820056c57c (expanded above)

Related sequences ?

No candidate equalities or related sequences.

References

[ASW52] Michael Aissen, I. J. Schoenberg and A. M. Whitney. On the generating functions of totally positive sequences I. Journal d’Analyse Mathématique, 2(1):93–103, 1952. doi:10.1007/BF02786970
[AW24] Christos A. Athanasiadis and David G. Wagner. Veronese sections and interlacing matrices of polynomials and formal power series. arXiv:2404.12989. arXiv
[Edr53] Albert Edrei. Proof of a Conjecture of Schoenberg on the Generating Function of a Totally Positive Sequence. Canadian Journal of Mathematics, 5:86–94, 1953. doi:10.4153/CJM-1953-010-3
[LW07] Lily L. Liu and Yi Wang. A unified approach to polynomial sequences with only real zeros. Advances in Applied Mathematics, 38(4):542–560, May 2007. doi:10.1016/j.aam.2006.02.003
[MW08] Shi-Mei Ma and Yi Wang. q-Eulerian polynomials and polynomials with only real zeros. The Electronic Journal of Combinatorics, 15(1):Research Paper 17, January 2008. doi:10.37236/741