a(n) = n^2*(n^2 + 1)/2.

Terms

a(0) =0a(1) =1a(2) =10a(3) =45a(4) =136a(5) =325a(6) =666a(7) =1225a(8) =2080a(9) =3321a(10) =5050a(11) =7381a(12) =10440a(13) =14365a(14) =19306a(15) =25425a(16) =32896a(17) =41905a(18) =52650a(19) =65341a(20) =80200a(21) =97461a(22) =117370a(23) =140185a(24) =166176a(25) =195625a(26) =228826a(27) =266085a(28) =307720a(29) =354061