A020073 a(n) = floor( Gamma(n+1/8)/Gamma(1/8) ).

1, 0, 0, 0, 0, 3, 19, 120, 861, 7000, 63875, 646742, 7195012, 87239530, 1145018831, 16173391001, 244622538902, 3944538439805, 67550220781671, 1224347751667801, 23415650750646695, 471239971356764753

Offset

0,6

Links

G. C. Greubel, Table of n, a(n) for n = 0..445

Maple

Digits := 64:f := proc(n, x) trunc(GAMMA(n+x)/GAMMA(x)); end;
seq(floor(pochhammer(1/8, n)), n = 0..25); # G. C. Greubel, Nov 17 2019

Mathematica

Floor[Pochhammer[1/8, Range[0, 25]]] (* G. C. Greubel, Nov 17 2019 *)

Prog

(PARI) A020073(n)=if(n==0, 1, truncate(prod(i=1, n, n-i+1/8)) );
for(n=0, 30, print(A020073(n), " ")) \\ R. J. Mathar, Feb 07 2008
(PARI) vector(26, n, my(x=1/8); gamma(n-1+x)\gamma(x) ) \\ G. C. Greubel, Nov 17 2019
(Magma) [Floor(Gamma(n+1/8)/Gamma(1/8)): n in [0..25]]; // G. C. Greubel, Nov 17 2019
(Sage) [floor(rising_factorial(1/8, n)) for n in (0..25)] # G. C. Greubel, Nov 17 2019

Crossrefs

Cf. A020070, A020071, A020072.

Sequence in context: A302443 A126809 A340644 * A138977 A163605 A294252

Adjacent sequences: A020070 A020071 A020072 * A020074 A020075 A020076

Keyword

nonn

Author

Simon Plouffe

Status

approved