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 A037974 #9 Aug 22 2021 00:12:56 %S A037974 13,26,27,39,41,53,54,67,78,79,82,83,94,107,108,117,118,119,123,124, %T A037974 125,134,135,148,159,160,163,164,175,188,189,201,203,215,216,229,234, %U A037974 235,236,237,238,239,246,247,248,249,250,251,256 %N A037974 Numbers whose maximal base-3 run length is 3. %Y A037974 Cf. A043277. %K A037974 nonn,base %O A037974 1,1 %A A037974 _Clark Kimberling_