A178820 → basis A013611 → x ↦ x/(x+1)

nonnegative coefficientsonly rational roots

Proved for all n all roots real, in [−1, 0]coefficients of one signHadamard kernel

Recurrence

\(\left(n + n x\right)\,P_{n}(x) = \left(6 + 24\,x + 18\,x^{2} + 2\,n + 8\,n x + 6\,n x^{2}\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
011
182432
240240360640
316014404320432010240
45606720302406048045360143360
51792268801612804838407257604354561835008
6537696768725760290304065318407838208391910422020096
71536032256029030401451520043545600783820807838208033592320251658240
842240101376010644480638668802395008005748019208622028807390310402771366402768240640
911264030412803649536025546752011496038403448811520689762304088683724806651279360221709312029527900160
1029286487859201186099209488793604981616640179338199044483454976076859228160864666316805764442112017293326336307090161664
1174547224600576369008640332107776019926466560836911595522510734786565380145971208070218956808070218956804842131374081320581283843126736191488
121863680670924801107025920110702592007472424960035867639808012553673932803228087582720605266421760080702189568007263197061120396174385152099043596288031267361914880
134587520178913280322043904035424829440265686220800143470559232057388223692801721646710784038737050992640645617516544007747410198528063387901624320316939508121607313988648960307863255777280
1411141120467927040912457728010949492736090333315072054199989043202438999506944083622840238080219509955624960439019911249920658529866874880718396218408960538797163806720248675614064640532876315852802990671627550720
Technical details
Node id
n-d628335cf92ba474 · revision 0 · JSON
Definition source
derived:mobius_x_over_x_plus_one
Fingerprint
f6-f9762973ec1089d7

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: no
  • γ-positive (gamma_positive): no
  • 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:      8,      24;
  2:     40,     240,      360;
  3:    160,    1440,     4320,      4320;
  4:    560,    6720,    30240,     60480,      45360;
  5:   1792,   26880,   161280,    483840,     725760,     435456;
  6:   5376,   96768,   725760,   2903040,    6531840,    7838208,    3919104;
  7:  15360,  322560,  2903040,  14515200,   43545600,   78382080,   78382080,   33592320;
  8:  42240, 1013760, 10644480,  63866880,  239500800,  574801920,  862202880,  739031040,  277136640;
  9: 112640, 3041280, 36495360, 255467520, 1149603840, 3448811520, 6897623040, 8868372480, 6651279360, 2217093120;
%F Formula
The row polynomials satisfy (n+n*x)*P(n,x) = (2*n+6+(8*n+24)*x+(6*n+18)*x^2)*P(n-1,x) for n >= 1, with P(0,x) = 1.
%t Mathematica
P[0, x_] := 1;
P[n_, x_] := P[n, x] = Expand[Together[((2*n + 6 + (8*n + 24)*x + (6*n + 18)*x^2)*P[n - 1, x])/(n + n*x)]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 1; for(n = 1, N, my(i = n + 1); v[i] = ((2*n + 6 + (8*n + 24)*x + (6*n + 18)*x^2)*v[i - 1])/(n + n*x)); 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.