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 A257647 #17 Apr 03 2023 10:36:13 %S A257647 0,0,0,0,0,0,0,0,0,0,0,271129,0,0,0,0,0,78557,0,0,0,0,0,327739,0,0,0, %T A257647 0,0,169073869,0,201446503145165177,0,0,0,1777613,0,0,0 %N A257647 Least k such that k*2^m + 1 has a covering set of modulus 2*n, or 0 if no such value exists. %H A257647 Chris K. Caldwell, <a href="https://t5k.org/glossary/xpage/SierpinskiNumber.html">The Prime Glossary: Sierpinski number</a>, The Prime Pages. %H A257647 Wikipedia, <a href="http://en.wikipedia.org/wiki/Sierpinski_number">Sierpinski number</a> %Y A257647 Cf. A076336, A257861, A258154. %K A257647 nonn %O A257647 1,12 %A A257647 _Arkadiusz Wesolowski_, Nov 05 2015