a(n) = 17*n^2 - 1.

Terms

a(0) =-1a(1) =16a(2) =67a(3) =152a(4) =271a(5) =424a(6) =611a(7) =832a(8) =1087a(9) =1376a(10) =1699a(11) =2056a(12) =2447a(13) =2872a(14) =3331a(15) =3824a(16) =4351a(17) =4912a(18) =5507a(19) =6136a(20) =6799a(21) =7496a(22) =8227a(23) =8992a(24) =9791a(25) =10624a(26) =11491a(27) =12392a(28) =13327a(29) =14296