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 A048307 #7 Oct 13 2019 16:41:42 %S A048307 0,1,2,3,4,5,6,7,8,9,11,22,33,44,55,66,77,88,99,100,111,122,133,144, %T A048307 155,166,177,188,199,200,211,222,233,244,255,266,277,288,299,300,311, %U A048307 322,333,344,355,366,377,388,399,400,411,422,433,444,455,466,477,488 %N A048307 Numbers whose decimal expansions, read from left to right, have run lengths that strictly increase. %Y A048307 Cf. A037015, A043636, A043713, A044821, A044959. %K A048307 nonn,base %O A048307 0,3 %A A048307 _Patrick De Geest_, Feb 15 1999