a(n) = (5*n^2 + 1)*n^2 / 6.

Terms

a(0) =0a(1) =1a(2) =14a(3) =69a(4) =216a(5) =525a(6) =1086a(7) =2009a(8) =3424a(9) =5481a(10) =8350a(11) =12221a(12) =17304a(13) =23829a(14) =32046a(15) =42225a(16) =54656a(17) =69649a(18) =87534a(19) =108661a(20) =133400a(21) =162141a(22) =195294a(23) =233289a(24) =276576a(25) =325625a(26) =380926a(27) =442989a(28) =512344a(29) =589541