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

A203709

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

Terms

    a(0) =2a(1) =1a(2) =3a(3) =10a(4) =55a(5) =311a(6) =2446a(7) =19447a(8) =196337a(9) =2014777a(10) =24828706a(11) =311108051a(12) =4507990477a(13) =66719239237

External references