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 A251757 #23 Dec 28 2014 23:45:35 %S A251757 39939,656709,762701,777149,779619,790841,869859,1106681,1156299, %T A251757 1254341,1320981,1330319,1730681,2251349,2344211,2882541,2924861, %U A251757 3079469,3292241,3419789,3580901,3661529,3781541,3784439,3848289,4358481,4384979,4507889,4524549 %N A251757 Odd numbers n not congruent to 1 mod 6 and that are not perfect powers such that for all k >= 1 the numbers n*4^k - 1 are composite. %C A251757 a(n) is a Riesel number if it is of the form 6*m + 5. %Y A251757 Cf. A101036, A251057. %K A251757 nonn %O A251757 1,1 %A A251757 _Arkadiusz Wesolowski_, Dec 15 2014