a(n) = 25*n^2 + n.

Terms

a(0) =26a(1) =102a(2) =228a(3) =404a(4) =630a(5) =906a(6) =1232a(7) =1608a(8) =2034a(9) =2510a(10) =3036a(11) =3612a(12) =4238a(13) =4914a(14) =5640a(15) =6416a(16) =7242a(17) =8118a(18) =9044a(19) =10020a(20) =11046a(21) =12122a(22) =13248a(23) =14424a(24) =15650a(25) =16926a(26) =18252a(27) =19628a(28) =21054a(29) =22530