A020123 Ceiling of Gamma(n+2/7)/Gamma(2/7).

1, 1, 1, 1, 3, 12, 63, 393, 2863, 23715, 220205, 2264966, 25561752, 314044379, 4172303890, 59604341273, 911094930877, 14837831731420, 256482519928832, 4689966078698629, 90449345803473559, 1834829586299035049

Offset: 0

Author

Simon Plouffe

Keywords

• nonn

Links

• Robert Israel, Table of n, a(n) for n = 0..450

Crossrefs

Cf. A220605.

Programs

Maple

Digits := 64:f := proc(n,x) ceil(GAMMA(n+x)/GAMMA(x)); end;

Mathematica

Table[Ceiling[Gamma[n+2/7]/Gamma[2/7]],{n,0,30}] (* Harvey P. Dale, Nov 24 2022 *)

Formula

a(n) ~ sqrt(2*Pi)*n^(n-3/14)*exp(-n)/Gamma(2/7). - Robert Israel, Jan 02 2017