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 A046287 #13 Oct 14 2019 03:58:41 %S A046287 5,8,9,17,21 %N A046287 Numbers k such that 2^k contains 2^1=2 as its largest proper substring of the form 2^m (probably finite). %Y A046287 Cf. A033921. %K A046287 nonn,base %O A046287 1,1 %A A046287 _Patrick De Geest_, Jun 15 1998