OFFSET
0,2
MAPLE
b := n -> `if`(n<2, 1-n, (n-2)!*bernoulli(n, 1/2)):
a := n -> denom(b(2*n)):
seq(a(n), n=0..54);
CROSSREFS
KEYWORD
nonn,frac
AUTHOR
Peter Luschny, Sep 24 2016
STATUS
approved