A072331 - OEIS

A072331

a(n) = 2^(n-1) * Sum_{k=0..n} ((n+k)!/(n-k)!)/k!.

%I #11 Jan 01 2024 13:54:46

%S 3,38,772,21768,786736,34703456,1807726656,108602413184,7392195003136,

%T 562241229891072,47257832090862592,4349969517278922752,

%U 435185983056255725568,47017486048144734052352

%N a(n) = 2^(n-1) * Sum_{k=0..n} ((n+k)!/(n-k)!)/k!.

%t Table[2^(n-1) Sum[((n+k)!/(n-k)!)/k!,{k,0,n}],{n,15}] (* _Harvey P. Dale_, May 22 2012 *)

%Y Cf. A001517.

%K easy,nonn

%O 1,1

%A _Benoit Cloitre_, Jul 31 2002

%E Definition clarified by _Harvey P. Dale_, May 22 2012