a(n) = RF(n+1,3)*C(n+2,n-1), where RF(a,n) is the rising factorial.

Terms

a(0) =0a(1) =24a(2) =240a(3) =1200a(4) =4200a(5) =11760a(6) =28224a(7) =60480a(8) =118800a(9) =217800a(10) =377520a(11) =624624a(12) =993720a(13) =1528800a(14) =2284800a(15) =3329280a(16) =4744224a(17) =6627960a(18) =9097200a(19) =12289200a(20) =16364040a(21) =21507024a(22) =27931200a(23) =35880000a(24) =45630000a(25) =57493800a(26) =71823024a(27) =89011440a(28) =109498200a(29) =133771200