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 A043497 #20 Apr 24 2021 21:07:56 %S A043497 2,12,20,21,23,24,25,26,27,28,29,32,42,52,62,72,82,92,102,112,120,121, %T A043497 123,124,125,126,127,128,129,132,142,152,162,172,182,192,200,201,203, %U A043497 204,205,206,207,208,209,210,211,213,214,215 %N A043497 Numbers having one 2 in base 10. %H A043497 Enrique Pérez Herrero, <a href="/A043497/b043497.txt">Table of n, a(n) for n = 1..2000</a> %H A043497 <a href="/index/Ar#10-automatic">Index entries for 10-automatic sequences</a>. %t A043497 Select[Range[9000],DigitCount[#,10,2]==1&] (* _Enrique Pérez Herrero_, Nov 29 2013 *) %Y A043497 Cf. A043489, A043493, A043501, A043505, A043509, A043513, A043517, A043521, A043525, A011532. %K A043497 nonn,base,easy %O A043497 1,1 %A A043497 _Clark Kimberling_