A159706 Numerator of Hermite(n, 2/21).

1, 4, -866, -10520, 2249356, 46111984, -9735212024, -282965467424, 58973337166480, 2232497686809664, -459200359680279584, -21527431036382354816, 4369052165472543104704, 245322538750961015791360, -49114261974304335175370624, -3225699756394083963693195776

Offset: 0

Author

N. J. A. Sloane, Nov 12 2009

Keywords

• sign
• frac

Examples

			Numerator of 1, 4/21, -866/441, -10520/9261, 2249356/194481, 46111984/4084101, ...
		

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..200
• DLMF Digital library of mathematical functions, Table 18.9.1 for H_n(x)

Crossrefs

Cf. A009965 (denominators).

Programs

Magma

[Numerator((&+[(-1)^k*Factorial(n)*(4/21)^(n-2*k)/( Factorial(k) *Factorial(n-2*k)): k in [0..Floor(n/2)]])): n in [0..30]]; // G. C. Greubel, May 22 2018

Maple

A159706 := proc(n)
        orthopoly[H](n,2/21) ;
        numer(%) ;
end proc: # R. J. Mathar, Feb 17 2014

Mathematica

Numerator[Table[HermiteH[n, 2/21], {n, 0, 30}]] (* Vladimir Joseph Stephan Orlovsky, Jun 17 2011 *)

PARI

a(n)=numerator(polhermite(n,2/21)) \\ Charles R Greathouse IV, Jan 29 2016

Formula

D-finite with recurrence a(n) - 4*a(n-1) + 882*(n-1)*a(n-2) = 0. [DLMF] - R. J. Mathar, Feb 17 2014

From G. C. Greubel, May 22 2018: (Start)

a(n) = 21^n * Hermite(n,2/21).

E.g.f.: exp(4*x-441*x^2).

a(n) = Sum_{k=0..floor(n/2)} (-1)^k*n!*(4/21)^(n-2k)/(k!*(n-2k)!). (End)