This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A077498 #8 Dec 05 2013 19:55:53 %S A077498 2,3,5,17,29,113,197,257,449,1373,3137,50177,65537,114689,268913, %T A077498 470597,614657,1075649,3294173,7340033,9834497,210827009,275365889, %U A077498 359661569,469762049,1129900997,1438646273,1927561217,7909306973,52613349377 %N A077498 Primes of the form 2^r*7^s + 1. %e A077498 197 = 2^2*7^2 + 1 is a member. %Y A077498 Cf. A005109, A077497, A077499, A077500. %K A077498 nonn %O A077498 1,1 %A A077498 _Amarnath Murthy_, Nov 07 2002 %E A077498 Corrected and extended by _Ray Chandler_, Aug 02 2003