a(n) = n^2*(n^3-n+2)/2.

Terms

a(0) =0a(1) =1a(2) =16a(3) =117a(4) =496a(5) =1525a(6) =3816a(7) =8281a(8) =16192a(9) =29241a(10) =49600a(11) =79981a(12) =123696a(13) =184717a(14) =267736a(15) =378225a(16) =522496a(17) =707761a(18) =942192a(19) =1234981a(20) =1596400a(21) =2037861a(22) =2571976a(23) =3212617a(24) =3974976a(25) =4875625a(26) =5932576a(27) =7165341a(28) =8594992a(29) =10244221