Expansion of e.g.f. exp( (x * (1+x))^2 ).

Terms

a(0) =1a(1) =0a(2) =2a(3) =12a(4) =36a(5) =240a(6) =2280a(7) =15120a(8) =122640a(9) =1330560a(10) =13335840a(11) =136382400a(12) =1657212480a(13) =20860519680a(14) =262278656640