G.f.: Sum_{k>=1} x^(2*k)/(1-x^(2*k)) * Product_{k>=1} (1+x^k)/(1-x^k).

Terms

a(0) =0a(1) =0a(2) =1a(3) =2a(4) =6a(5) =12a(6) =24a(7) =44a(8) =79a(9) =134a(10) =222a(11) =358a(12) =566a(13) =876a(14) =1334a(15) =2000a(16) =2960a(17) =4326a(18) =6253a(19) =8946a(20) =12680a(21) =17816a(22) =24832a(23) =34352a(24) =47192a(25) =64404a(26) =87354a(27) =117796a(28) =157976a(29) =210764