OFFSET
0,3
FORMULA
a(n) = denominator(Bernoulli(n)^2*(2^(n+2) - 4)).
EXAMPLE
Rational sequence starts: 0, 1, 1/3, 0, 1/15, 0, 1/7, 0, 17/15, 0, 775/33, 0, 477481/455, ...
MAPLE
a := s -> `if`(s = 0, 0, -4*s^2*Zeta(1 - s)^2*(1 - 2^s)):
seq(denom(a(s)), s = 0..24);
CROSSREFS
KEYWORD
nonn,frac
AUTHOR
Peter Luschny, Jun 13 2020
STATUS
approved