a(n) = 12*n + 1.

Terms

a(0) =1a(1) =13a(2) =25a(3) =37a(4) =49a(5) =61a(6) =73a(7) =85a(8) =97a(9) =109a(10) =121a(11) =133a(12) =145a(13) =157a(14) =169a(15) =181a(16) =193a(17) =205a(18) =217a(19) =229a(20) =241a(21) =253a(22) =265a(23) =277a(24) =289a(25) =301a(26) =313a(27) =325a(28) =337a(29) =349