a(n) = gcd(k^n + 1, (k+1)^n + 1) for the smallest k at which the GCD exceeds 1.

Terms

a(0) =5a(1) =7a(2) =17a(3) =11a(4) =5a(5) =29a(6) =17a(7) =19a(8) =25a(9) =23a(10) =17a(11) =53a(12) =145a(13) =61a(14) =353a(15) =137a(16) =5a(17) =191a(18) =41a(19) =43a(20) =5a(21) =47a(22) =97a(23) =11a(24) =265a(25) =19a(26) =337a(27) =59a(28) =25a(29) =5953