A085880 → basis A013609 → D

palindromicγ-positivenonnegative coefficientsonly rational roots

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

Recurrence

\(\left(-2\,n + n^{2}\right)\,P_{n}(x) = \left(12 + 12\,x - 20\,n - 20\,n x + 8\,n^{2} + 8\,n^{2} x\right)\,P_{n-1}(x)\)
\(P_{1}(x) = 0\)
\(P_{2}(x) = 2\)

Rows ?

nx0x1x2x3x4x5x6Pn(1)
10
222
3161632
4120240120480
5896268826888967168
667202688040320268806720107520
750688253440506880506880253440506881622016
83843842306304576576076876805765760230630438438424600576
Technical details
Node id
n-a551c6c6bb4d5813 · revision 0 · JSON
Definition source
derived:derivative
Fingerprint
f6-77a7ed3b1d5f257e

Observed on the stored rows ?

  • Degrees: -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 (affine: slope 1, intercept -2)
  • 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:        2;
   3:       16,        16;
   4:      120,       240,       120;
   5:      896,      2688,      2688,        896;
   6:     6720,     26880,     40320,      26880,       6720;
   7:    50688,    253440,    506880,     506880,     253440,      50688;
   8:   384384,   2306304,   5765760,    7687680,    5765760,    2306304,    384384;
   9:  2928640,  20500480,  61501440,  102502400,  102502400,   61501440,  20500480,   2928640;
  10: 22404096, 179232768, 627314688, 1254629376, 1568286720, 1254629376, 627314688, 179232768, 22404096;
%F Formula
The row polynomials satisfy (n^2-2*n)*P(n,x) = (8*n^2-20*n+12+(8*n^2-20*n+12)*x)*P(n-1,x) for n >= 3, with P(1,x) = 0, P(2,x) = 2.
%t Mathematica
P[1, x_] := 0;
P[2, x_] := 2;
P[n_, x_] := P[n, x] = Expand[Together[((8*n^2 - 20*n + 12 + (8*n^2 - 20*n + 12)*x)*P[n - 1, x])/(n^2 - 2*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] = 2; for(n = 3, N, my(i = n); v[i] = ((8*n^2 - 20*n + 12 + (8*n^2 - 20*n + 12)*x)*v[i - 1])/(n^2 - 2*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.