a(n) = (-1)^(n+1) * Sum_{k=0..n} 16^k * B(2k) * C(2n+1,2k) where B(k) is the k-th Bernoulli number.

A078794

a(n) = (-1)^(n+1) * Sum_{k=0..n} 16^k * B(2k) * C(2n+1,2k) where B(k) is the k-th Bernoulli number.

Terms

    a(0) =9a(1) =15a(2) =441a(3) =12447a(4) =555753a(5) =35135919a(6) =2990414745a(7) =329655706431

External references