OFFSET
0,2
COMMENTS
See A239792 for references.
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).
MAPLE
CROSSREFS
KEYWORD
nonn
AUTHOR
Peter Luschny, Mar 26 2014
STATUS
approved