a(n) = 49*n^2 + n.

Terms

a(0) =50a(1) =198a(2) =444a(3) =788a(4) =1230a(5) =1770a(6) =2408a(7) =3144a(8) =3978a(9) =4910a(10) =5940a(11) =7068a(12) =8294a(13) =9618a(14) =11040a(15) =12560a(16) =14178a(17) =15894a(18) =17708a(19) =19620a(20) =21630a(21) =23738a(22) =25944a(23) =28248a(24) =30650a(25) =33150a(26) =35748a(27) =38444a(28) =41238a(29) =44130