a(n) = (2*n - 15)*n^2.

Terms

a(0) =0a(1) =-13a(2) =-44a(3) =-81a(4) =-112a(5) =-125a(6) =-108a(7) =-49a(8) =64a(9) =243a(10) =500a(11) =847a(12) =1296a(13) =1859a(14) =2548a(15) =3375a(16) =4352a(17) =5491a(18) =6804a(19) =8303a(20) =10000a(21) =11907a(22) =14036a(23) =16399a(24) =19008a(25) =21875a(26) =25012a(27) =28431a(28) =32144a(29) =36163