G.f.: Sum_{n>=0} (n+1)*(n+2)*(n+3)/3! * x^n * (1 + x^n)^n.

Terms

a(0) =1a(1) =4a(2) =14a(3) =20a(4) =55a(5) =56a(6) =154a(7) =120a(8) =305a(9) =280a(10) =566a(11) =364a(12) =1189a(13) =560a(14) =1520a(15) =1376a(16) =2429a(17) =1140a(18) =4570a(19) =1540a(20) =5226a(21) =4544a(22) =6304a(23) =2600a(24) =14685a(25) =3556a(26) =10934a(27) =11980a(28) =18215a(29) =4960