A085880 → D → D

palindromicγ-positivenonnegative coefficientsonly rational roots

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

Recurrence

\(\left(-3\,n + n^{2}\right)\,P_{n}(x) = \left(6 + 6\,x - 10\,n - 10\,n x + 4\,n^{2} + 4\,n^{2} x\right)\,P_{n-1}(x)\)
\(P_{1}(x) = 0\)
\(P_{2}(x) = 0\)
\(P_{3}(x) = 4\)

Rows ?

nx0x1x2x3x4x5Pn(1)
10
20
344
4303060
5168336168672
6840252025208406720
73960158402376015840396063360
818018900901801801801809009018018576576
Technical details
Node id
n-49114448249ebd1e · revision 0 · JSON
Definition source
derived:derivative
Fingerprint
f6-77a7ed3b1d5f257e

Observed on the stored rows ?

  • Degrees: -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 (affine: slope 1, intercept -3)
  • 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 = 1, …, ascending powers of x
%e Example
Triangle begins:
   1:      0;
   2:      0;
   3:      4;
   4:     30,      30;
   5:    168,     336,     168;
   6:    840,    2520,    2520,      840;
   7:   3960,   15840,   23760,    15840,     3960;
   8:  18018,   90090,  180180,   180180,    90090,   18018;
   9:  80080,  480480, 1201200,  1601600,  1201200,  480480,   80080;
  10: 350064, 2450448, 7351344, 12252240, 12252240, 7351344, 2450448, 350064;
%F Formula
The row polynomials satisfy (n^2-3*n)*P(n,x) = (4*n^2-10*n+6+(4*n^2-10*n+6)*x)*P(n-1,x) for n >= 4, with P(1,x) = 0, P(2,x) = 0, P(3,x) = 4.
%t Mathematica
P[1, x_] := 0;
P[2, x_] := 0;
P[3, x_] := 4;
P[n_, x_] := P[n, x] = Expand[Together[((4*n^2 - 10*n + 6 + (4*n^2 - 10*n + 6)*x)*P[n - 1, x])/(n^2 - 3*n)]];
Table[CoefficientList[P[n, x], x], {n, 1, 10}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N)); v[1] = 0; v[2] = 0; v[3] = 4; for(n = 4, N, my(i = n); v[i] = ((4*n^2 - 10*n + 6 + (4*n^2 - 10*n + 6)*x)*v[i - 1])/(n^2 - 3*n)); v};
row(n, p) = {my(c = Vecrev(p)); c};
T(N) = {my(v = P(N)); concat(vector(#v, i, row(i, v[i])))};
T(10)

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. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.