Unique prime factors of 2^n+1 are of the form kn+1. These are the values for k.

Terms

a(0) =2a(1) =2a(2) =0a(3) =4a(4) =2a(5) =2a(6) =6a(7) =32a(8) =2a(9) =4a(10) =62a(11) =20a(12) =210a(13) =2a(14) =8a(15) =22a(16) =4096a(17) =2570a(18) =2a(19) =6a(20) =9198a(21) =3084a(22) =258a(23) =18a(24) =96a(25) =121574a(26) =4a(27) =28a(28) =10a(29) =162