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A020113
a(n) = ceiling of Gamma(n + 2/9)/Gamma(2/9).
2
1, 1, 1, 1, 2, 9, 43, 267, 1928, 15845, 146123, 1493701, 16762640, 204876709, 2708925369, 38526938569, 586465620431, 9513775620310, 163848357905336, 2985681188497228, 57391427290002262, 1160582196308934616, 24630133277222945727, 547336295049398793928
OFFSET
0,5
FORMULA
a(n) ~ sqrt(2*Pi)*n^(n-5/18)*exp(-n)/Gamma(2/9) as n -> infinity. - Robert Israel, Jun 07 2015
EXAMPLE
Gamma(6 + 2/9) = 176.09917208972649...
Gamma(2/9) = 4.1065795667...
176.09917208972649.../4.1065795667... = 42.8822... hence a(6) = 43.
MAPLE
Digits := 64:f := proc(n, x) ceil(GAMMA(n+x)/GAMMA(x)); end;
MATHEMATICA
Table[Ceiling[Gamma[n + 2/9]/Gamma[2/9]], {n, 0, 19}] (* Alonso del Arte, Jun 07 2015 *)
PROG
(Magma) [Ceiling(Gamma(n + 2/9)/Gamma(2/9)): n in [0..30]]; // Vincenzo Librandi, Jun 08 2015
CROSSREFS
Sequence in context: A334680 A324619 A292099 * A345414 A272199 A260074
KEYWORD
nonn
AUTHOR
STATUS
approved