a(n) = 49*n^2 + 7.

Terms

a(0) =56a(1) =203a(2) =448a(3) =791a(4) =1232a(5) =1771a(6) =2408a(7) =3143a(8) =3976a(9) =4907a(10) =5936a(11) =7063a(12) =8288a(13) =9611a(14) =11032a(15) =12551a(16) =14168a(17) =15883a(18) =17696a(19) =19607a(20) =21616a(21) =23723a(22) =25928a(23) =28231a(24) =30632a(25) =33131a(26) =35728a(27) =38423a(28) =41216a(29) =44107