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 A048306 #6 Oct 13 2019 16:42:02 %S A048306 0,1,2,3,4,5,6,7,8,10,20,30,40,50,60,70,80,81,91,101,111,121,131,141, %T A048306 151,161,162,172,182,192,202,212,222,232,242,243,253,263,273,283,293, %U A048306 303,313,323,324,334,344,354,364,374,384,394,404,405,415,425,435,445 %N A048306 Numbers whose base-9 expansions, read from left to right, have run lengths that strictly increase. %Y A048306 Cf. A037015, A043698, A043712, A044820, A044958. %K A048306 nonn,base %O A048306 0,3 %A A048306 _Patrick De Geest_, Feb 15 1999