OFFSET
1,1
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..150
FORMULA
a(n) ~ 16^n * n! / (Pi*n^2). - Vaclav Kotesovec, Sep 05 2014
MAPLE
a:= proc(n) option remember; local i; `if`(n<1, 1, add(a(n-i) *(2*i)!^2 /i!^3 /(i+1), i=1..n)) end: seq(a(n), n=1..20); # Alois P. Heinz, Apr 01 2009
MATHEMATICA
a[n_] := a[n] = If[n < 1, 1, Sum[a[n - i] *(2 i)!^2 /i!^3 /(i + 1), {i, 1, n}]]; Array[a, 20] (* Jean-François Alcover, Mar 03 2016, adapted from Maple *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Dec 05 2003
EXTENSIONS
More terms from Alois P. Heinz, Apr 01 2009
STATUS
approved