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 A237880 #38 Jun 05 2021 16:56:51 %S A237880 0,0,0,0,1,16,134,1345,13420 %N A237880 Conjectured number of distinct integers < 10^n that are Sierpiński or Riesel or simultaneously Sierpiński and Riesel numbers. %H A237880 Wikipedia, <a href="http://en.wikipedia.org/wiki/Riesel_number">Riesel number</a> %H A237880 Wikipedia, <a href="http://en.wikipedia.org/wiki/Sierpinski_number">Sierpinski number</a> %F A237880 a(n) = A236320(n) + A236321(n) for n <= 9. %Y A237880 Cf. A076335, A076336, A076337, A101036, A236320, A236321. %K A237880 nonn,more %O A237880 1,6 %A A237880 _Arkadiusz Wesolowski_, Feb 14 2014 %E A237880 Definition clarified by _Arkadiusz Wesolowski_, Jun 05 2021