A376827 → basis A013609

palindromicγ-positivenonnegative coefficientsonly rational roots

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

Recurrence

\(\left(n\right)\,P_{n}(x) = \left(-12 - 24\,x - 12\,x^{2} + 12\,n + 24\,n x + 12\,n x^{2}\right)\,P_{n-2}(x) + \left(-2 - 2\,x + 4\,n + 4\,n x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)
\(P_{1}(x) = 2 + 2\,x\)

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
011
1224
212241248
35616816856448
43041216182412163044864
51632816016320163208160163252224
6902454144135360180480135360541449024577536
7503043521281056384176064017606401056384352128503046438912
Technical details
Node id
n-ab1ed4a574b7f1a3 · revision 0 · JSON
Definition source
derived:basis_map_A013609
Fingerprint
f6-77a7ed3b1d5f257e

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: yes
  • γ-positive (gamma_positive): yes
  • 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,        2;
  2:      12,       24,       12;
  3:      56,      168,      168,        56;
  4:     304,     1216,     1824,      1216,       304;
  5:    1632,     8160,    16320,     16320,      8160,      1632;
  6:    9024,    54144,   135360,    180480,    135360,     54144,      9024;
  7:   50304,   352128,  1056384,   1760640,   1760640,   1056384,    352128,    50304;
  8:  283392,  2267136,  7934976,  15869952,  19837440,  15869952,   7934976,  2267136,   283392;
  9: 1607168, 14464512, 57858048, 135002112, 202503168, 202503168, 135002112, 57858048, 14464512, 1607168;
%F Formula
The row polynomials satisfy n*P(n,x) = (12*n-12+(24*n-24)*x+(12*n-12)*x^2)*P(n-2,x) + (4*n-2+(4*n-2)*x)*P(n-1,x) for n >= 2, with P(0,x) = 1, P(1,x) = 2 + 2*x.
%t Mathematica
P[0, x_] := 1;
P[1, x_] := 2 + 2*x;
P[n_, x_] := P[n, x] = Expand[Together[((12*n - 12 + (24*n - 24)*x + (12*n - 12)*x^2)*P[n - 2, x] + (4*n - 2 + (4*n - 2)*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 + 2*x; for(n = 2, N, my(i = n + 1); v[i] = ((12*n - 12 + (24*n - 24)*x + (12*n - 12)*x^2)*v[i - 2] + (4*n - 2 + (4*n - 2)*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.