A156992 → basis A013609 → D

palindromicγ-positivenonnegative coefficientsonly rational roots

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

Recurrence

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

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13Pn(1)
00
144
2484896
357611525762304
476802304023040768061440
51152004608006912004608001152001843200
61935360967680019353600193536009676800193536061931520
736126720216760320541900800722534400541900800216760320361267202312110080
8743178240520224768015606743040260112384002601123840015606743040520224768074317824095126814720
9167215104001337720832004682022912009364045824001170505728000936404582400468202291200133772083200167215104004280706662400
1040874803200036787322880001471492915200034334834688000515022520320005150225203200034334834688000147149291520003678732288000408748032000209278992384000
1110790948044800107909480448000485592662016000129491376537600022660990894080002719318907289600226609908940800012949137653760004855926620160001079094804480001079094804480011049930797875200
123060705263616003366775789977600168338789498880005050163684966400010100327369932800014140458317905920014140458317905920010100327369932800050501636849664000168338789498880003366775789977600306070526361600626832437988556800
1392841392996352001114096715956224006127531937759232002042510645919744000459564895331942400073530383253110784008578544712862924800735303832531107840045956489533194240002042510645919744000612753193775923200111409671595622400928413929963520038027834571305779200
1429994911583436800038993385058467840002339603103508070400085785447128629248000214463617821573120000386034512078831616000514712682771775488000514712682771775488000386034512078831616000214463617821573120000857854471286292480002339603103508070400038993385058467840002999491158343680002457183156915142656000
Technical details
Node id
n-4e7185fe9feea02f · 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:           4;
  2:          48,           48;
  3:         576,         1152,          576;
  4:        7680,        23040,        23040,         7680;
  5:      115200,       460800,       691200,       460800,        115200;
  6:     1935360,      9676800,     19353600,     19353600,       9676800,      1935360;
  7:    36126720,    216760320,    541900800,    722534400,     541900800,    216760320,     36126720;
  8:   743178240,   5202247680,  15606743040,  26011238400,   26011238400,  15606743040,   5202247680,    743178240;
  9: 16721510400, 133772083200, 468202291200, 936404582400, 1170505728000, 936404582400, 468202291200, 133772083200, 16721510400;
%F Formula
The row polynomials satisfy (n-1)*P(n,x) = (2*n^2+2*n+(2*n^2+2*n)*x)*P(n-1,x) for n >= 2, with P(0,x) = 0, P(1,x) = 4.
%t Mathematica
P[0, x_] := 0;
P[1, x_] := 4;
P[n_, x_] := P[n, x] = Expand[Together[((2*n^2 + 2*n + (2*n^2 + 2*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] = 4; for(n = 2, N, my(i = n + 1); v[i] = ((2*n^2 + 2*n + (2*n^2 + 2*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.