Numbers k such that k | 4^k + 1.

Terms

a(0) =1a(1) =5a(2) =25a(3) =125a(4) =205a(5) =625a(6) =1025a(7) =2525a(8) =3125a(9) =5125a(10) =8405a(11) =12625a(12) =15625a(13) =25625a(14) =42025a(15) =63125a(16) =78125a(17) =103525a(18) =128125a(19) =168305a(20) =202525a(21) =210125a(22) =255025a(23) =315625a(24) =344605a(25) =390625a(26) =517625a(27) =640625a(28) =841525a(29) =875125