E.g.f.: 1 + Sum_{n>=1} 2*exp(n^2*x) / 2^n.

A249940

E.g.f.: 1 + Sum_{n>=1} 2*exp(n^2*x) / 2^n.

Terms

    a(0) =3a(1) =12a(2) =300a(3) =18732a(4) =2183340a(5) =408990252a(6) =112366270380

External references