cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A160308 Numerator of Hermite(n, 10/31).

Original entry on oeis.org

1, 20, -1522, -107320, 6629452, 957665200, -44555729720, -11934909680800, 360754594036880, 190726263132718400, -2425807704995582240, -3714274931510759292800, -22999072131198586137920, 85206055577740180606380800, 2278775927824931485369685120
Offset: 0

Views

Author

N. J. A. Sloane, Nov 12 2009

Keywords

Examples

			Numerators of 1, 20/31, -1522/961, -107320/29791, 6629452/923521, ...
		

Crossrefs

Cf. A009975 (denominators).

Programs

  • Magma
    [Numerator((&+[(-1)^k*Factorial(n)*(20/31)^(n-2*k)/( Factorial(k) *Factorial(n-2*k)): k in [0..Floor(n/2)]])): n in [0..30]]; // G. C. Greubel, Oct 04 2018
  • Mathematica
    Table[31^n*HermiteH[n, 10/31], {n, 0, 30}] (* G. C. Greubel, Oct 04 2018 *)
  • PARI
    a(n)=numerator(polhermite(n, 10/31)) \\ Charles R Greathouse IV, Jan 29 2016
    
  • PARI
    x='x+O('x^30); Vec(serlaplace(exp(20*x - 961*x^2))) \\ G. C. Greubel, Oct 04 2018
    

Formula

From G. C. Greubel, Oct 04 2018: (Start)
a(n) = 31^n * Hermite(n, 10/31).
a(n+2) = 20*a(n+1) - 1922*(n+1)*a(n)
E.g.f.: exp(20*x - 961*x^2).
a(n) = numerator(Sum_{k=0..floor(n/2)} (-1)^k*n!*(20/31)^(n-2*k)/(k!*(n-2*k)!)). (End)