a(n) = 49n^2 - 28n - 20.

Terms

a(0) =1a(1) =120a(2) =337a(3) =652a(4) =1065a(5) =1576a(6) =2185a(7) =2892a(8) =3697a(9) =4600a(10) =5601a(11) =6700a(12) =7897a(13) =9192a(14) =10585a(15) =12076a(16) =13665a(17) =15352a(18) =17137a(19) =19020a(20) =21001a(21) =23080a(22) =25257a(23) =27532a(24) =29905a(25) =32376a(26) =34945a(27) =37612a(28) =40377a(29) =43240