A085880 → x ↦ x+1 → x ↦ x+1

nonnegative coefficientsonly rational roots

Proved for all n all roots real, in (−∞, −1]coefficients of one signHadamard kernelinterlacing (weak)

Recurrence

\(\left(n\right)\,P_{n}(x) = \left(-18 - 6\,x + 12\,n + 4\,n x\right)\,P_{n-1}(x)\)
\(P_{1}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
111
2314
31812232
4135135455320
511341512756168143584
610206170101134037806304243008
79622819245616038071280178202376132540672
89382232189187218918712162154054058108190094297028736
993822302501928029189160194594408108100216216036036034320143093716480
10956987462870962383827949842977294321488647164962157211027016157528813127448621274544128
11991787004330595668049589350204407942240257129964010285198562856999605441904068023805038801679617611882496
121041376354238183799654636396660906363966609042426444060197990072286599669076157134978026189163029099070193993858786246566354944
13110546105292442184421168810671438808900746043120675559532340360298417248140116051152400331574728340241140123559128012355912874884322080123489862254592
1411844225567005132497745700102649954914001254610560060010455088000500627305280030027880234668009293411556002323352889004302505350057366738005215158002897310074290049855175065600
1512791763612360596948968576801293389431916401724519242555201580809305675601053872870450405269364352252020073768960960585484928028013010776178402168462696402628439632021903663601123264802674440717914520944640
Technical details
Node id
n-0a892fb0722e2e5d · revision 0 · JSON
Definition source
derived:shift_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 -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 = 1, …, ascending powers of x
%e Example
Triangle begins:
   1:        1;
   2:        3,         1;
   3:       18,        12,         2;
   4:      135,       135,        45,         5;
   5:     1134,      1512,       756,       168,        14;
   6:    10206,     17010,     11340,      3780,       630,       42;
   7:    96228,    192456,    160380,     71280,     17820,     2376,      132;
   8:   938223,   2189187,   2189187,   1216215,    405405,    81081,     9009,     429;
   9:  9382230,  25019280,  29189160,  19459440,   8108100,  2162160,   360360,   34320,   1430;
  10: 95698746, 287096238, 382794984, 297729432, 148864716, 49621572, 11027016, 1575288, 131274, 4862;
%F Formula
The row polynomials satisfy n*P(n,x) = (12*n-18+(4*n-6)*x)*P(n-1,x) for n >= 2, with P(1,x) = 1.
%t Mathematica
P[1, x_] := 1;
P[n_, x_] := P[n, x] = Expand[Together[((12*n - 18 + (4*n - 6)*x)*P[n - 1, x])/(n)]];
Table[CoefficientList[P[n, x], x], {n, 1, 10}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N)); v[1] = 1; for(n = 2, N, my(i = n); v[i] = ((12*n - 18 + (4*n - 6)*x)*v[i - 1])/(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.