E.g.f.: 1/Product_{k>0} (1 - x^(2*k)/(2*k)) (even powers only).

A309319

E.g.f.: 1/Product_{k>0} (1 - x^(2*k)/(2*k)) (even powers only).

Terms

    a(0) =1a(1) =1a(2) =12a(3) =300a(4) =15960a(5) =1232280a(6) =157006080a(7) =25418352960

External references