Primitive prime factors of the sequence k^2 + 1 (A002522) in the order that they are found.

Terms

a(0) =2a(1) =5a(2) =17a(3) =13a(4) =37a(5) =41a(6) =101a(7) =61a(8) =29a(9) =197a(10) =113a(11) =257a(12) =181a(13) =401a(14) =97a(15) =53a(16) =577a(17) =313a(18) =677a(19) =73a(20) =157a(21) =421a(22) =109a(23) =89a(24) =613a(25) =1297a(26) =137a(27) =761a(28) =1601a(29) =353