A239795 a(n) = A239793(n)/2^(3*n).

1, 3, 5, 21, 45, 11, 91, 45, 17, 1995, 3465, 115, 2925, 189, 145, 341, 1309, 1, 9139, 65, 2255, 148995, 108675, 1645, 270725, 21879, 583, 4389, 4959, 59, 1548729, 27027, 60775, 130985, 15525, 1065, 66047553, 2567565, 39, 2133, 56457, 1411, 8161615, 2639

Offset: 0

Author

Peter Luschny, Mar 26 2014

Keywords

• nonn

Comments

See A239792 for references.

Crossrefs

Cf. A220412, A239792.

Programs

Maple

b := proc(n) option remember; if n < 1 then 1 else
-add(binomial(n-1, k-1)*bernoulli(k)*b(n-k)/k, k= 2..n)/2 fi end:
A239795 := n -> denom(b(2*n))/2^(3*n):
seq(A239795(n), n=0..43);

Formula

Let b(n) = -Sum_{2<=k<=n} (C(n-1, k-1)*Bernoulli(k)*b(n-k)/k)/2

for n>0 and otherwise 1. Then a(n) = denominator(b(2*n))/2^(3*n).