A196347 → basis A013609 → θ+1

nonnegative coefficientsonly rational roots

Proved for all n all roots real, in (−∞, 0]coefficients of one signHadamard kernelinterlacing (weak)

Recurrence

\(\left(1 + n x\right)\,P_{n}(x) = \left(2\,n + 4\,n x + 2\,n x^{2} + 2\,n^{2} x + 2\,n^{2} x^{2}\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
011
1246
28322464
348288432192960
4384307269126144192018432
53840384001152001536009600023040430080
646080552960207360036864003456000165888032256011796480
76451209031680406425609031680011289600081285120316108805160960371589120
Technical details
Node id
n-7eb70857c2b50e89 · revision 0 · JSON
Definition source
derived:theta_plus_one
Fingerprint
f6-e99c3824c4864868

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

Matches ?

No OEIS matches.

Submission text ?

Atlas rows n = 0, …, ascending powers of x
%e Example
Triangle begins:
  0:         1;
  1:         2,          4;
  2:         8,         32,          24;
  3:        48,        288,         432,         192;
  4:       384,       3072,        6912,        6144,         1920;
  5:      3840,      38400,      115200,      153600,        96000,        23040;
  6:     46080,     552960,     2073600,     3686400,      3456000,      1658880,       322560;
  7:    645120,    9031680,    40642560,    90316800,    112896000,     81285120,     31610880,     5160960;
  8:  10321920,  165150720,   867041280,  2312110080,   3612672000,   3468165120,   2023096320,   660602880,    92897280;
  9: 185794560, 3344302080, 20065812480, 62426972160, 117050572800, 140460687360, 109247201280, 53508833280, 15049359360, 1857945600;
%F Formula
The row polynomials satisfy (1+n*x)*P(n,x) = (2*n+(2*n^2+4*n)*x+(2*n^2+2*n)*x^2)*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[Together[((2*n + (2*n^2 + 4*n)*x + (2*n^2 + 2*n)*x^2)*P[n - 1, x])/(1 + n*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] = ((2*n + (2*n^2 + 4*n)*x + (2*n^2 + 2*n)*x^2)*v[i - 1])/(1 + n*x)); 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)

polytool c48629374597

Properties

Proof chains ? JSON

Same fingerprint ?

References

  1. [Bra06] Petter Brändén. On linear transformations preserving the Pólya frequency property. Transactions of the American Mathematical Society, 358(8):3697–3716, February 2006. doi:10.1090/s0002-9947-06-03856-6
  2. [Bra15] Petter Brändén. Unimodality, log-concavity, real-rootedness and beyond. Handbook of enumerative combinatorics, :437–483, March 2015. doi:10.1201/b18255-10
  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
  4. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.