a(n) = (7*n + 5)^2.

Terms

a(0) =25a(1) =144a(2) =361a(3) =676a(4) =1089a(5) =1600a(6) =2209a(7) =2916a(8) =3721a(9) =4624a(10) =5625a(11) =6724a(12) =7921a(13) =9216a(14) =10609a(15) =12100a(16) =13689a(17) =15376a(18) =17161a(19) =19044a(20) =21025a(21) =23104a(22) =25281a(23) =27556a(24) =29929a(25) =32400a(26) =34969a(27) =37636a(28) =40401a(29) =43264