a(n) = 4*n^2 + 1.

Terms

a(0) =1a(1) =5a(2) =17a(3) =37a(4) =65a(5) =101a(6) =145a(7) =197a(8) =257a(9) =325a(10) =401a(11) =485a(12) =577a(13) =677a(14) =785a(15) =901a(16) =1025a(17) =1157a(18) =1297a(19) =1445a(20) =1601a(21) =1765a(22) =1937a(23) =2117a(24) =2305a(25) =2501a(26) =2705a(27) =2917a(28) =3137a(29) =3365