Real-rooted atlas

A269947 → basis A013609

nonnegative coefficients only rational roots

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

Recurrence
\(P_{n}(x) = \left(2\,x + 3\,n - 3\,n^{2} + n^{3}\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
011
1123
226412
31858488132
450416601460320163960
5327601089089822023720168032265320
641277601378792812593536318516025912073926433960960
789572392030002358962760373168716366792625993602122304286721287437450240

Show all 15 stored rows

Computed in your browser ?

Technical details
Node id
n-7cfac8d939582bff · revision 1 · JSON
Definition source
derived:basis_map_A013609
Fingerprint
f6-84bd2520c71a96df

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 0)
  • 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): yes

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;
  2:               2,               6,               4;
  3:              18,              58,              48,               8;
  4:             504,            1660,            1460,             320,             16;
  5:           32760,          108908,           98220,           23720,           1680,           32;
  6:         4127760,        13787928,        12593536,         3185160,         259120,         7392,         64;
  7:       895723920,      3000235896,      2760373168,       716366792,       62599360,      2122304,      28672,      128;
  8:    308129028480,   1033872596064,    955568841584,    251950922784,    22966913424,    855271296,   14107776,   101376,    256;
  9: 158070191610240, 530992899837792, 492274560924720, 131161961071360, 12285928432080, 484688001696, 8947831680, 80221440, 334080, 512;
%F Formula
The row polynomials satisfy P(n,x) = (n^3-3*n^2+3*n+2*x)*P(n-1,x) for n >= 1, with P(0,x) = 1.
%t Mathematica
P[0, x_] := 1;
P[n_, x_] := P[n, x] = Expand[(n^3 - 3*n^2 + 3*n + 2*x)*P[n - 1, x]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 1; for(n = 1, N, my(i = n + 1); v[i] = (n^3 - 3*n^2 + 3*n + 2*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 - 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-e62c7427c0d251dd
  • 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-e62c7427c0d251dd
  • 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-e62c7427c0d251dd

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.