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 A043494 #16 Apr 24 2021 21:07:42 %S A043494 11,101,110,112,113,114,115,116,117,118,119,121,131,141,151,161,171, %T A043494 181,191,211,311,411,511,611,711,811,911,1001,1010,1012,1013,1014, %U A043494 1015,1016,1017,1018,1019,1021,1031,1041,1051,1061,1071 %N A043494 Numbers having two 1's in base 10. %H A043494 Daniel Starodubtsev, <a href="/A043494/b043494.txt">Table of n, a(n) for n = 1..10000</a> %t A043494 Select[Range[1100],DigitCount[#,10,1]==2&] (* _Harvey P. Dale_, Nov 30 2013 *) %Y A043494 Subsequence of A011531. %K A043494 nonn,base %O A043494 1,1 %A A043494 _Clark Kimberling_