OFFSET
0,1
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..400
FORMULA
E.g.f.: 2*B(x)/(2-B(x)) where B(x) is e.g.f. of A114902.
a(n) ~ c * d^n * n^(n + 1/2), where d = 0.6907524084725166379194613015033714490019226066943600905783847741049876032..., c = 4.71633079866926561049991146534865892961540468329142429184529629611133729... - Vaclav Kotesovec, Sep 21 2019
MAPLE
b:= proc(n, i) option remember;
`if`(n=0, `if`(i=0, 1, 2), add(`if`(i=j, 0, b(n-j,
`if`(j>n-j, -1, j))*binomial(n, j)), j=0..n))
end:
a:= n-> b(n, -1):
seq(a(n), n=0..25); # Alois P. Heinz, Sep 04 2015
MATHEMATICA
b[n_, i_] := b[n, i] = If[n == 0, If[i == 0, 1, 2], Sum[If[i == j, 0, b[n - j, If[j > n - j, -1, j]]*Binomial[n, j]], {j, 0, n}]]; a[n_] := b[n, -1]; Table[a[n], {n, 0, 25}] (* Jean-François Alcover, Feb 25 2017, after Alois P. Heinz *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Christian G. Bower, Jan 05 2006
STATUS
approved