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 A161749 #9 Oct 01 2013 21:35:30 %S A161749 3,5,127,3299,1967249047,8191,30450469261,131071,524287, %T A161749 476562280296181,70358283824461 %N A161749 Smallest prime of the form x^(2n+1) - y^(2n-1), x,y >= 1. %C A161749 For even n > 4 = 2m, x^(2m) - y^(2m-2) = (x^m)^2 - y^((m-1))^2 is divisible by x^m - y^(m-1) which is not prime. This accounts for the omission of even powers in the definition. %K A161749 nonn %O A161749 1,1 %A A161749 _Cino Hilliard_, Jun 17 2009 %E A161749 Incorrect program removed; definition confined to odd powers; added terms a(8)..a(11). - R. J. Mathar, Feb 27 2012