a(n) = 4^(2*n)*(4^(2*n)-1)*Bernoulli(2*n)/(2*n).

A047682

a(n) = 4^(2*n)*(4^(2*n)-1)*Bernoulli(2*n)/(2*n).

Terms

    a(0) =20a(1) =-544a(2) =66560a(3) =-17895424a(4) =8329625600

External references