a(n) = (2*n - 13)*n^2.

Terms

a(0) =0a(1) =-11a(2) =-36a(3) =-63a(4) =-80a(5) =-75a(6) =-36a(7) =49a(8) =192a(9) =405a(10) =700a(11) =1089a(12) =1584a(13) =2197a(14) =2940a(15) =3825a(16) =4864a(17) =6069a(18) =7452a(19) =9025a(20) =10800a(21) =12789a(22) =15004a(23) =17457a(24) =20160a(25) =23125a(26) =26364a(27) =29889a(28) =33712a(29) =37845