OFFSET
0,4
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..450
FORMULA
a(n) ~ c * d^n * n^(n + 1/2), where d = 0.37565358657373546999489873158654700..., c = 2.0427954030382239202983023897265... - Vaclav Kotesovec, Sep 21 2019
MAPLE
b:= proc(n, i) option remember;
`if`(n=0, 1, add(`if`(i=j, 0, b(n-j,
`if`(j>n-j, 0, j)) *binomial(n, j)), j=1..n))
end:
a:= n-> b(n, 0):
seq(a(n), n=0..25); # Alois P. Heinz, Sep 04 2015
MATHEMATICA
b[n_, i_] := b[n, i] = If[n==0, 1, Sum[If[i==j, 0, b[n-j, If[j>n-j, 0, j]]* Binomial[n, j]], {j, 1, n}]]; a[n_] := b[n, 0]; Table[a[n], {n, 0, 25}] (* Jean-François Alcover, Feb 20 2017, after Alois P. Heinz *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Christian G. Bower, Jan 05 2006
STATUS
approved