a(n) = 25*n^2 + 5.

Terms

a(0) =30a(1) =105a(2) =230a(3) =405a(4) =630a(5) =905a(6) =1230a(7) =1605a(8) =2030a(9) =2505a(10) =3030a(11) =3605a(12) =4230a(13) =4905a(14) =5630a(15) =6405a(16) =7230a(17) =8105a(18) =9030a(19) =10005a(20) =11030a(21) =12105a(22) =13230a(23) =14405a(24) =15630a(25) =16905a(26) =18230a(27) =19605a(28) =21030a(29) =22505