A376827 → basis A007318

nonnegative coefficientsonly rational roots

Proved for all n all roots real, in (−∞, −1]coefficients of one signHadamard kernel

Recurrence

\(\left(n\right)\,P_{n}(x) = \left(-12 - 12\,x - 3\,x^{2} + 12\,n + 12\,n x + 3\,n x^{2}\right)\,P_{n-2}(x) + \left(-2 - x + 4\,n + 2\,n x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)
\(P_{1}(x) = 2 + x\)

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
011
1213
21212327
35684427189
4304608456152191539
516324080408020405105112393
6902427072338402256084601692141102789
750304176064264096220080110040330125502393859491
Technical details
Node id
n-eb97e93fd65cf0d3 · revision 0 · JSON
Definition source
derived:shift_x_plus_one
Fingerprint
f6-11aec07ce60b6d61

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,       1;
  2:      12,      12,        3;
  3:      56,      84,       42,        7;
  4:     304,     608,      456,      152,       19;
  5:    1632,    4080,     4080,     2040,      510,      51;
  6:    9024,   27072,    33840,    22560,     8460,    1692,     141;
  7:   50304,  176064,   264096,   220080,   110040,   33012,    5502,    393;
  8:  283392, 1133568,  1983744,  1983744,  1239840,  495936,  123984,  17712,  1107;
  9: 1607168, 7232256, 14464512, 16875264, 12656448, 6328224, 2109408, 452016, 56502, 3139;
%F Formula
The row polynomials satisfy n*P(n,x) = (12*n-12+(12*n-12)*x+(3*n-3)*x^2)*P(n-2,x) + (4*n-2+(2*n-1)*x)*P(n-1,x) for n >= 2, with P(0,x) = 1, P(1,x) = 2 + x.
%t Mathematica
P[0, x_] := 1;
P[1, x_] := 2 + x;
P[n_, x_] := P[n, x] = Expand[Together[((12*n - 12 + (12*n - 12)*x + (3*n - 3)*x^2)*P[n - 2, x] + (4*n - 2 + (2*n - 1)*x)*P[n - 1, x])/(n)]];
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] = 2 + x; for(n = 2, N, my(i = n + 1); v[i] = ((12*n - 12 + (12*n - 12)*x + (3*n - 3)*x^2)*v[i - 2] + (4*n - 2 + (2*n - 1)*x)*v[i - 1])/(n)); 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. [Bra15] Petter Brändén. Unimodality, log-concavity, real-rootedness and beyond. Handbook of enumerative combinatorics, :437–483, March 2015. doi:10.1201/b18255-10
  2. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.