A063967 → basis A013610

nonnegative coefficients

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

Recurrence
\(P_{n}(x) = \left(2 + 3\,x\right)\,P_{n-2}(x) + \left(2 + 3\,x\right)\,P_{n-1}(x)\)
\(P_{1}(x) = 1\)
\(P_{2}(x) = 2 + 3\,x\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
111
2235
3615930
416607227175
544216387297811025
61207321746202511342436000
732823887110110439396413172935125
8896758427072527046026440338145802187205625
9244823616982802300403305612979181640255030165611203750
10668872432344304941544162988218489871371978640791170586196837046875
1118272219504117331236709207435638101751399512721599019324275705708075904941253125
1249920658752391104013777776319684325124481257841776459160652508926489754481889568177147241500000
13136384196108812803472501504481311542282410521123189688473058760072107524421016430123253599962001455314411413765625
1437260857985924128854417799998451802999210739618281630512018183401601315270596289287620384007065141160312852019475815943238276328125
1510179841704633613146307261857691219828197364577580540784400355010128226635989530020072742463103957700176154419039940814668865367243478296948450468750

Generated b-files: A057088 (row sums) ?

Computed in your browser ?

Technical details
Node id
n-51fcbaaf07b9691b · revision 1 · JSON
Definition source
derived:basis_map_A013610
Fingerprint
f6-87f1729e0e693bae

Observed on the stored rows ?

  • Degrees: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 (affine: slope 1, intercept -1)
  • 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 ?

A generated b-file is computed from the node's definition along the row alignment of its OEIS link and starts at the entry's offset. It is an identification on a finite prefix, not a proof that the node and the OEIS entry agree for every n.

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 = 1, …, ascending powers of x
%e Example
Triangle begins:
   1:    1;
   2:    2,     3;
   3:    6,    15,      9;
   4:   16,    60,     72,     27;
   5:   44,   216,    387,    297,      81;
   6:  120,   732,   1746,   2025,    1134,     243;
   7:  328,  2388,   7110,  11043,    9396,    4131,     729;
   8:  896,  7584,  27072,  52704,   60264,   40338,   14580,   2187;
   9: 2448, 23616,  98280, 230040,  330561,  297918,  164025,  50301,   6561;
  10: 6688, 72432, 344304, 941544, 1629882, 1848987, 1371978, 640791, 170586, 19683;
%F Formula
The row polynomials satisfy P(n,x) = (2+3*x)*P(n-2,x) + (2+3*x)*P(n-1,x) for n >= 3, with P(1,x) = 1, P(2,x) = 2 + 3*x.
%t Mathematica
P[1, x_] := 1;
P[2, x_] := 2 + 3*x;
P[n_, x_] := P[n, x] = Expand[(2 + 3*x)*P[n - 2, x] + (2 + 3*x)*P[n - 1, x]];
Table[CoefficientList[P[n, x], x], {n, 1, 10}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N)); v[1] = 1; v[2] = 2 + 3*x; for(n = 3, N, my(i = n); v[i] = (2 + 3*x)*v[i - 2] + (2 + 3*x)*v[i - 1]); v};
row(n, p) = {my(c = Vecrev(p)); c};
T(N) = {my(v = P(N)); concat(vector(#v, i, row(i, v[i])))};
T(10)

Generated with polytool c48629374597.

Proved properties

  • Real-rooted. Every row P_n, n >= 1, 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-52226b414d15e69f
  • Coefficients of one sign. Every nonzero row, n >= 1: 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-52226b414d15e69f
  • Hadamard kernel (Malo). Rows P_n, n >= 1, 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-52226b414d15e69f

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

No candidate equalities or related sequences.

References

  1. [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
  2. [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