a(n) = (n^5 - 5*n^4 + 5*n^3 + 5*n^2 + 114*n + 120)/120.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =6a(5) =12a(6) =28a(7) =64a(8) =135a(9) =262a(10) =473a(11) =804a(12) =1300a(13) =2016a(14) =3018a(15) =4384a(16) =6205a(17) =8586a(18) =11647a(19) =15524a(20) =20370a(21) =26356a(22) =33672a(23) =42528a(24) =53155a(25) =65806a(26) =80757a(27) =98308a(28) =118784a(29) =142536