A020040 a(n) = round( Gamma(n+1/5)/Gamma(1/5) ).

1, 0, 0, 1, 2, 7, 37, 229, 1647, 13507, 124269, 1267543, 14196477, 173197024, 2286200718, 32464050199, 493453563029, 7993947721071, 137495900802424, 2502425394604114, 48046567576398986, 970540665043259525

Offset: 0

Author

Simon Plouffe

Keywords

• nonn

Comments

Gamma(n+1/5)/Gamma(1/5) = 1, 1/5, 6/25, 66/125, 1056/625, 22176/3125, 576576/15625, 17873856/78125, ... - R. J. Mathar, Sep 04 2016

Links

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

Crossrefs

Cf. A008548, A020085, A020130.

Programs

Magma

[Round(Gamma(n+1/5)/Gamma(1/5)): n in [0..30]]; // G. C. Greubel, Dec 06 2019

Maple

Digits := 64:f := proc(n,x) round(GAMMA(n+x)/GAMMA(x)); end;
seq( round(pochhammer(1/5, n)), n=0..30); # G. C. Greubel, Dec 06 2019

Mathematica

Table[Round[Pochhammer[1/5,n]], {n,0,30}] (* G. C. Greubel, Dec 06 2019 *)

PARI

x=1/5; vector(30, n, round(gamma(n-1+x)/gamma(x)) ) \\ G. C. Greubel, Dec 06 2019

Sage

[round(rising_factorial(1/5,n)) for n in (0..30)] # G. C. Greubel, Dec 06 2019