A020068 - OEIS

%I #24 Sep 08 2022 08:44:44

%S 1,0,0,0,1,8,42,266,1927,15844,146122,1493700,16762639,204876708,

%T 2708925368,38526938568,586465620430,9513775620309,163848357905335,

%U 2985681188497227,57391427290002261,1160582196308934615

%N a(n) = floor( Gamma(n+2/9) / Gamma(2/9) ).

%H G. C. Greubel, <a href="/A020068/b020068.txt">Table of n, a(n) for n = 0..445</a>

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

%p seq(floor(pochhammer(2/9,n)), n = 0..25); # _G. C. Greubel_, Nov 13 2019

%t Floor[Pochhammer[2/9, Range[0, 25]]] (* _G. C. Greubel_, Nov 13 2019 *)

%o (PARI) x=2/9; vector(26, n, gamma(n-1+x)\gamma(x) ) \\ _G. C. Greubel_, Nov 13 2019

%o (Magma) [Floor(Gamma(n+2/9)/Gamma(2/9)): n in [0..25]]; // _G. C. Greubel_, Nov 13 2019

%o (Sage) [floor(rising_factorial(2/9, n)) for n in (0..25)] # _G. C. Greubel_, Nov 13 2019

%Y Cf. A020064, A020065, A020066, A020067, A020069.

%Y Cf. A020023, A020113.

%K nonn

%O 0,6

%A _Simon Plouffe_