a(n) = (n - 1)*(n - 2)*(5*n^4 + 3*n^3 + 34*n^2 - 264*n + 180)/360.

Terms

a(0) =1a(1) =0a(2) =0a(3) =1a(4) =19a(5) =107a(6) =386a(7) =1086a(8) =2597a(9) =5530a(10) =10788a(11) =19647a(12) =33847a(13) =55693a(14) =88166a(15) =135044a(16) =201033a(17) =291908a(18) =414664a(19) =577677a(20) =790875a(21) =1065919a(22) =1416394a(23) =1858010a(24) =2408813a(25) =3089406a(26) =3923180a(27) =4936555a(28) =6159231a(29) =7624449