A120909 → basis A013610 → D

nonnegative coefficientsonly rational roots

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

Recurrence

\(\left(-1 + n\right)\,P_{n}(x) = \left(3\,n + 6\,n x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 0\)
\(P_{1}(x) = 18\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13Pn(1)
00
11818
2108216324
3486194419444374
4194411664233281555252488
5729058320174960233280116640590490
6262442624401049760209952020995208398086377292
79185411022485511240146966402204496017635968587865666961566
83149284408992264539528817984017635968021163161614108774440310784688747536
910628821700611211904278447617113611904278401904684544190468454410883911682720977926973568802
10354294063772920510183360238085568071425670401428513408019046845440163258675208162933760181398528069735688020
111169170223383404021045063601122403392039284118720942818849281571364748801795845427201346884070405986151424011972302848690383311398
12382637528418025448418025440505081526402020326105605656913095681131382619136161626088448016162608844801077507256320431002902528783641640966778308875544
13124357194298457265632830299216218868661440984908976480315170872473673539870243841260683489894415758543623680140075943321608404556599296305620239974450936706662466088511536554
1440176939610446004296125352051552919248378048459624189024016546470804864441239221463048824784429260813237176643891214707974048768011766379239014464180250394624213934167982083291294892032640550188738908
Technical details
Node id
n-01adf842a5cd4b2f · revision 0 · JSON
Definition source
derived:derivative
Fingerprint
f6-11aec07ce60b6d61

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: 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:       0;
  1:      18;
  2:     108,      216;
  3:     486,     1944,      1944;
  4:    1944,    11664,     23328,     15552;
  5:    7290,    58320,    174960,    233280,     116640;
  6:   26244,   262440,   1049760,   2099520,    2099520,     839808;
  7:   91854,  1102248,   5511240,  14696640,   22044960,   17635968,    5878656;
  8:  314928,  4408992,  26453952,  88179840,  176359680,  211631616,  141087744,   40310784;
  9: 1062882, 17006112, 119042784, 476171136, 1190427840, 1904684544, 1904684544, 1088391168, 272097792;
%F Formula
The row polynomials satisfy (n-1)*P(n,x) = (3*n+6*n*x)*P(n-1,x) for n >= 2, with P(0,x) = 0, P(1,x) = 18.
%t Mathematica
P[0, x_] := 0;
P[1, x_] := 18;
P[n_, x_] := P[n, x] = Expand[Together[((3*n + 6*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] = 18; for(n = 2, N, my(i = n + 1); v[i] = ((3*n + 6*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.