a(n) = (9*n^4+10*n^3-3*n^2-4*n)/12.

Terms

a(0) =0a(1) =1a(2) =17a(3) =80a(4) =240a(5) =565a(6) =1141a(7) =2072a(8) =3480a(9) =5505a(10) =8305a(11) =12056a(12) =16952a(13) =23205a(14) =31045a(15) =40720a(16) =52496a(17) =66657a(18) =83505a(19) =103360a(20) =126560a(21) =153461a(22) =184437a(23) =219880a(24) =260200a(25) =305825a(26) =357201a(27) =414792a(28) =479080a(29) =550565