OFFSET
0,4
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..500
FORMULA
E.g.f.: exp(cosh(x)-1)*Product_{k>0} (1+sinh(x^(2*k-1)/(2*k-1)!)).
MAPLE
with(combinat):
b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0, add(
`if`(j=0 or irem(i, 2)=0 or irem(j, 2)=1, multinomial(
n, n-i*j, i$j)/j!*b(n-i*j, i-1), 0), j=0..n/i)))
end:
a:= n-> b(n$2):
seq(a(n), n=0..30); # Alois P. Heinz, Mar 08 2015
MATHEMATICA
max = 26; f[x_] = Exp[Cosh[x]-1]*Product[1+Sinh[x^(2*k-1)/(2*k-1)!], {k, 0, max}]; CoefficientList[f[x] + O[x]^max, x]*Range[0, max-1]! (* Jean-François Alcover, Jul 01 2015 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Vladeta Jovovic, Aug 05 2007, Aug 05 2007
EXTENSIONS
More terms from Max Alekseyev, Jan 31 2010
STATUS
approved