G.f.: A(x) = Product_{n>=1} [ (1-x)^4*(1 + 4x + 10x^2 +...+ n(n+1)(n+2)/3!*x^(n-1)) ].

Terms

a(0) =1a(1) =-4a(2) =-4a(3) =36a(4) =-64a(5) =256a(6) =-1328a(7) =4488a(8) =-11406a(9) =17700a(10) =14716a(11) =-194508a(12) =662768a(13) =-1374476a(14) =2210780a(15) =-5820284a(16) =25965483a(17) =-95963664a(18) =259794360a(19) =-545959440a(20) =952758316a(21) =-1278120568a(22) =60070208a(23) =8030404744a(24) =-34554134770a(25) =94549651780a(26) =-196087124052a(27) =330754522268a(28) =-511020392180