a(n) = 625*n^2 - 886*n + 314.

Terms

a(0) =53a(1) =1042a(2) =3281a(3) =6770a(4) =11509a(5) =17498a(6) =24737a(7) =33226a(8) =42965a(9) =53954a(10) =66193a(11) =79682a(12) =94421a(13) =110410a(14) =127649a(15) =146138a(16) =165877a(17) =186866a(18) =209105a(19) =232594a(20) =257333a(21) =283322a(22) =310561a(23) =339050a(24) =368789a(25) =399778a(26) =432017a(27) =465506a(28) =500245a(29) =536234