a(n) = 64*n^2 - n.

Terms

a(0) =63a(1) =254a(2) =573a(3) =1020a(4) =1595a(5) =2298a(6) =3129a(7) =4088a(8) =5175a(9) =6390a(10) =7733a(11) =9204a(12) =10803a(13) =12530a(14) =14385a(15) =16368a(16) =18479a(17) =20718a(18) =23085a(19) =25580a(20) =28203a(21) =30954a(22) =33833a(23) =36840a(24) =39975a(25) =43238a(26) =46629a(27) =50148a(28) =53795a(29) =57570