G.f.: Product_{n>0} ( (1+x^n)/(1-x^n) )^(n^4).

Terms

a(0) =1a(1) =2a(2) =34a(3) =228a(4) =1414a(5) =8872a(6) =52876a(7) =301136a(8) =1662614a(9) =8929406a(10) =46738920a(11) =239036116a(12) =1197187780a(13) =5882369976a(14) =28397283056a(15) =134864166352a(16) =630819797174