a(n) = (2*n)! [x^(2*n)] log(1 + tanh(x)^2)/2.

A024299

a(n) = (2*n)! [x^(2*n)] log(1 + tanh(x)^2)/2.

Terms

    a(0) =0a(1) =1a(2) =-14a(3) =496a(4) =-34544a(5) =4055296a(6) =-724212224a(7) =183218384896

External references