Real-rooted atlas

A144441 → x ↦ x+1

nonnegative coefficients

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

Recurrence

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

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
011
1213
21616133
3168252861507
4241648322852436110537
544160110400926882863221861278067
69811842943552320516815044162725521093618917809
7256874248990598412031996876034960224062002527332546861336936555

All 15 rows

Technical details
Node id
n-6e03aa63410fab4d · revision 0 · JSON
Definition source
derived:shift_x_plus_one
Fingerprint
f6-bb41b383faa3577c

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,            1;
  2:          16,           16,            1;
  3:         168,          252,           86,            1;
  4:        2416,         4832,         2852,          436,            1;
  5:       44160,       110400,        92688,        28632,         2186,           1;
  6:      981184,      2943552,      3205168,      1504416,       272552,       10936,          1;
  7:    25687424,     89905984,    120319968,     76034960,     22406200,     2527332,      54686,         1;
  8:   774547456,   3098189824,   4919283776,   3914186944,   1613388992,   317687872,   23117852,    273436,       1;
  9: 26437363200, 118968134400, 218589786880, 209879626880, 111632692320, 31974977200, 4371448928, 209920032, 1367186, 1;
%F Formula
The row polynomials satisfy P(n,x) = (4+4*x)*P(n-2,x) + (4*n-2+(4*n-3)*x)*P(n-1,x) - (4*x+4*x^2)*d/dx 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[(4 + 4*x)*P[n - 2, x] + (4*n - 2 + (4*n - 3)*x)*P[n - 1, x] - (4*x + 4*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; v[2] = 2 + x; for(n = 2, N, my(i = n + 1); v[i] = (4 + 4*x)*v[i - 2] + (4*n - 2 + (4*n - 3)*x)*v[i - 1] - (4*x + 4*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. [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