A120910 → basis A013610 → D

palindromicγ-positivenonnegative coefficientsonly rational roots

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

Recurrence

\(\left(-1 + n\right)\,P_{n}(x) = \left(3\,n + 3\,n x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 0\)
\(P_{1}(x) = 9\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13Pn(1)
00
199
25454108
3243486243972
4972291629169727776
53645145802187014580364558320
613122656101312201312206561013122419904
745927275562688905918540688905275562459272939328
815746411022483306744551124055112403306744110224815746420155392
9531441425152814880348297606963720087029760696148803484251528531441136048896
101771470159432306377292014880348022320522022320522014880348063772920159432301771470906992640
115845851584585102630632957015021201227628710147315445212276287107015021202630632955845851058458515986151424
1219131876210450636105225318031567595406313519080883892671288389267126313519080315675954010522531802104506361913187639182082048
1362178597746143164410378740213679291340307784055154924544882457453023628492454488243077840551513679291340410378740274614316462178597254683533312
1420088469826115010741566900644457453023628143632559070258538606326344718141768344718141768258538606326143632559070574530236281566900644426115010742008846981645647446016
Technical details
Node id
n-baf28ec5de3ccf78 · 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 -1)
  • 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:      0;
  1:      9;
  2:     54,      54;
  3:    243,     486,      243;
  4:    972,    2916,     2916,      972;
  5:   3645,   14580,    21870,    14580,     3645;
  6:  13122,   65610,   131220,   131220,    65610,    13122;
  7:  45927,  275562,   688905,   918540,   688905,   275562,    45927;
  8: 157464, 1102248,  3306744,  5511240,  5511240,  3306744,  1102248,  157464;
  9: 531441, 4251528, 14880348, 29760696, 37200870, 29760696, 14880348, 4251528, 531441;
%F Formula
The row polynomials satisfy (n-1)*P(n,x) = (3*n+3*n*x)*P(n-1,x) for n >= 2, with P(0,x) = 0, P(1,x) = 9.
%t Mathematica
P[0, x_] := 0;
P[1, x_] := 9;
P[n_, x_] := P[n, x] = Expand[Together[((3*n + 3*n*x)*P[n - 1, x])/(n - 1)]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 0; v[2] = 9; for(n = 2, N, my(i = n + 1); v[i] = ((3*n + 3*n*x)*v[i - 1])/(n - 1)); 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. [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.