A124860 → basis A013610

nonnegative coefficientsonly rational roots

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

Recurrence

\(P_{n}(x) = \left(8 + 24\,x + 18\,x^{2}\right)\,P_{n-2}(x) + \left(2 + 3\,x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)
\(P_{1}(x) = 2 + 3\,x\)

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
011
1235
212362775
340180270135625
41761056237623768916875
56725040151202268017010510365625
62752247689288018576020898012538831347671875
7108801142405140801285200192780017350208675101858956640625
Technical details
Node id
n-fc842da63eb6b354 · revision 0 · JSON
Definition source
derived:basis_map_A013610
Fingerprint
f6-f06e51c139cfae05

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:      2,       3;
  2:     12,      36,       27;
  3:     40,     180,      270,      135;
  4:    176,    1056,     2376,     2376,       891;
  5:    672,    5040,    15120,    22680,     17010,      5103;
  6:   2752,   24768,    92880,   185760,    208980,    125388,     31347;
  7:  10880,  114240,   514080,  1285200,   1927800,   1735020,    867510,    185895;
  8:  43776,  525312,  2757888,  8273664,  15513120,  18615744,  13961808,   5983632,  1121931;
  9: 174592, 2356992, 14141952, 49496832, 111367872, 167051808, 167051808, 107390448, 40271418, 6711903;
%F Formula
The row polynomials satisfy P(n,x) = (8+24*x+18*x^2)*P(n-2,x) + (2+3*x)*P(n-1,x) for n >= 2, with P(0,x) = 1, P(1,x) = 2 + 3*x.
%t Mathematica
P[0, x_] := 1;
P[1, x_] := 2 + 3*x;
P[n_, x_] := P[n, x] = Expand[(8 + 24*x + 18*x^2)*P[n - 2, x] + (2 + 3*x)*P[n - 1, x]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 1; v[2] = 2 + 3*x; for(n = 2, N, my(i = n + 1); v[i] = (8 + 24*x + 18*x^2)*v[i - 2] + (2 + 3*x)*v[i - 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. [Bra15] Petter Brändén. Unimodality, log-concavity, real-rootedness and beyond. Handbook of enumerative combinatorics, :437–483, March 2015. doi:10.1201/b18255-10
  2. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.