A376827 → basis A013611

nonnegative coefficientsonly rational roots

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

Recurrence

\(\left(n\right)\,P_{n}(x) = \left(-12 - 48\,x - 48\,x^{2} + 12\,n + 48\,n x + 48\,n x^{2}\right)\,P_{n-2}(x) + \left(-2 - 4\,x + 4\,n + 8\,n x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)
\(P_{1}(x) = 2 + 4\,x\)

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
011
1246
2124848108
3563366724481512
4304243272969728486424624
51632163206528013056013056052224396576
690241082885414401443840216576017326085775366578496
7503047042564225536140851202817024033804288225361926438912110014848
Technical details
Node id
n-e3c2e6e725bdc109 · revision 0 · JSON
Definition source
derived:basis_map_A013611
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,        4;
  2:      12,       48,        48;
  3:      56,      336,       672,        448;
  4:     304,     2432,      7296,       9728,       4864;
  5:    1632,    16320,     65280,     130560,     130560,      52224;
  6:    9024,   108288,    541440,    1443840,    2165760,    1732608,     577536;
  7:   50304,   704256,   4225536,   14085120,   28170240,   33804288,   22536192,    6438912;
  8:  283392,  4534272,  31739904,  126959616,  317399040,  507838464,  507838464,  290193408,   72548352;
  9: 1607168, 28929024, 231432192, 1080016896, 3240050688, 6480101376, 8640135168, 7405830144, 3702915072, 822870016;
%F Formula
The row polynomials satisfy n*P(n,x) = (12*n-12+(48*n-48)*x+(48*n-48)*x^2)*P(n-2,x) + (4*n-2+(8*n-4)*x)*P(n-1,x) for n >= 2, with P(0,x) = 1, P(1,x) = 2 + 4*x.
%t Mathematica
P[0, x_] := 1;
P[1, x_] := 2 + 4*x;
P[n_, x_] := P[n, x] = Expand[Together[((12*n - 12 + (48*n - 48)*x + (48*n - 48)*x^2)*P[n - 2, x] + (4*n - 2 + (8*n - 4)*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 + 4*x; for(n = 2, N, my(i = n + 1); v[i] = ((12*n - 12 + (48*n - 48)*x + (48*n - 48)*x^2)*v[i - 2] + (4*n - 2 + (8*n - 4)*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.