a(n) = 81*n^2 - 72*n + 17.

Terms

a(0) =17a(1) =26a(2) =197a(3) =530a(4) =1025a(5) =1682a(6) =2501a(7) =3482a(8) =4625a(9) =5930a(10) =7397a(11) =9026a(12) =10817a(13) =12770a(14) =14885a(15) =17162a(16) =19601a(17) =22202a(18) =24965a(19) =27890a(20) =30977a(21) =34226a(22) =37637a(23) =41210a(24) =44945a(25) =48842a(26) =52901a(27) =57122a(28) =61505a(29) =66050