A156992 → basis A008277 → reverse

nonnegative coefficients

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

Recurrence

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

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
011
1246
26302460
324216456192888
4120168066007800192018120
5720144009000020520015192023040485280
65040136080123480045864006809040335160032256016445520
74032014112001749888095961600237928320244702080830188805160960685722240
Technical details
Node id
n-0030376a5cb28a95 · revision 0 · JSON
Definition source
derived:reversal
Fingerprint
f6-b5f1389370a379f1

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): no

Matches ?

No OEIS matches.

Submission text ?

Atlas rows n = 0, …, ascending powers of x
%e Example
Triangle begins:
  0:       1;
  1:       2,         4;
  2:       6,        30,         24;
  3:      24,       216,        456,         192;
  4:     120,      1680,       6600,        7800,         1920;
  5:     720,     14400,      90000,      205200,       151920,        23040;
  6:    5040,    136080,    1234800,     4586400,      6809040,      3351600,       322560;
  7:   40320,   1411200,   17498880,    95961600,    237928320,    244702080,     83018880,      5160960;
  8:  362880,  15966720,  259096320,  1966083840,   7323281280,  12909093120,   9556444800,   2287958400,    92897280;
  9: 3628800, 195955200, 4027968000, 40388544000, 210858681600, 568487808000, 741019104000, 405137376000, 69567724800, 1857945600;
%F Formula
The row polynomials satisfy P(n,x) = (n+1+(n^2+2*n+1)*x)*P(n-1,x) - (n+1)*x^2*d/dx 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 + 1 + (n^2 + 2*n + 1)*x)*P[n - 1, x] - (n + 1)*x^2*D[P[n - 1, x], 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 + 1 + (n^2 + 2*n + 1)*x)*v[i - 1] - (n + 1)*x^2*deriv(v[i - 1], 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. [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
  5. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.