A376827 → basis A013610

nonnegative coefficientsonly rational roots

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

Recurrence

\(\left(n\right)\,P_{n}(x) = \left(-12 - 36\,x - 27\,x^{2} + 12\,n + 36\,n x + 27\,n x^{2}\right)\,P_{n-2}(x) + \left(-2 - 3\,x + 4\,n + 6\,n x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)
\(P_{1}(x) = 2 + 3\,x\)

Rows ?

nx0x1x2x3x4x5x6x7Pn(1)
011
1235
212362775
356252378189875
4304182441044104153911875
516321224036720550804131012393159375
69024812163045606091206852604111561027892203125
7503045281922376864594216089132408021916401095885949130703125
Technical details
Node id
n-edc6f5add0304545 · 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:      56,      252,       378,       189;
  4:     304,     1824,      4104,      4104,       1539;
  5:    1632,    12240,     36720,     55080,      41310,      12393;
  6:    9024,    81216,    304560,    609120,     685260,     411156,     102789;
  7:   50304,   528192,   2376864,   5942160,    8913240,    8021916,    4010958,    859491;
  8:  283392,  3400704,  17853696,  53561088,  100427040,  120512448,   90384336,  38736144,   7263027;
  9: 1607168, 21696768, 130180608, 455632128, 1025172288, 1537758432, 1537758432, 988558992, 370709622, 61784937;
%F Formula
The row polynomials satisfy n*P(n,x) = (12*n-12+(36*n-36)*x+(27*n-27)*x^2)*P(n-2,x) + (4*n-2+(6*n-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[Together[((12*n - 12 + (36*n - 36)*x + (27*n - 27)*x^2)*P[n - 2, x] + (4*n - 2 + (6*n - 3)*x)*P[n - 1, x])/(n)]];
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] = ((12*n - 12 + (36*n - 36)*x + (27*n - 27)*x^2)*v[i - 2] + (4*n - 2 + (6*n - 3)*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 - 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.