a(n) = [x^n] f(x)^n, where f(x) = (1 - x^7)^7/((1 - x^3)^3 * (1 - x^4)^4).

Terms

a(0) =1a(1) =0a(2) =0a(3) =9a(4) =16a(5) =0a(6) =171a(7) =539a(8) =528a(9) =3654a(10) =16500a(11) =29282a(12) =101851a(13) =483340a(14) =1215445a(15) =3416634a(16) =14564880a(17) =44585475a(18) =124007202a(19) =462804166a(20) =1555048516a(21) =4547401595a(22) =15500748802a(23) =53459717443a(24) =164998563675a(25) =538593687500