A020087 a(n) = floor( Gamma(n + 1/4)/Gamma(1/4) ).

1, 0, 0, 0, 2, 9, 50, 318, 2310, 19060, 176310, 1807181, 20330788, 249052161, 3299941145, 47024161317, 717118460090, 11653174976468, 201017268344078, 3668565147279423, 70619879085128903, 1430052551473860292

Offset

0,5

Links

G. C. Greubel, Table of n, a(n) for n = 0..450

Maple

Digits:= 64: x:=1/4: A020087:= proc(n, x) trunc(GAMMA(n+x)/GAMMA(x)); end;
seq(floor(pochhammer(1/4, n)), n = 0..25); # G. C. Greubel, Nov 17 2019

Mathematica

Floor[Pochhammer[1/4, Range[0, 25]]] (* G. C. Greubel, Nov 19 2018 *)

Prog

(PARI) vector(26, n, my(x=1/4); gamma(n-1+x)\gamma(x) ) \\ G. C. Greubel, Nov 19 2018
(Magma) [Truncate(Gamma(n + 1/4)/Gamma(1/4)): n in [0..30]]; // G. C. Greubel, Nov 19 2018
(Sage) [int(gamma(n + 1/4)/gamma(1/4))  for n in range(30)] # G. C. Greubel, Nov 19 2018

Crossrefs

Cf. A020042, A020087.

Sequence in context: A192945 A271960 A175895 * A277378 A026945 A246464

Adjacent sequences: A020084 A020085 A020086 * A020088 A020089 A020090

Keyword

nonn

Author

Simon Plouffe

Status

approved