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 A130228 #10 Feb 23 2018 15:47:50 %S A130228 1,5,10,11,15,50,51,100,101,105,110,111,500,501,505,511,1000,1001, %T A130228 1005,1010,1011,1015,1050,1051,5001,5005,5010,5011,5015,5051,5111, %U A130228 10001,10005,10010,10011,10015,10050,10051,10100,10101,10105,10110,10111 %N A130228 Roman numerals with "i" replaced by "1", "v" replaced by "5", "x" replaced by 10, etc., sorted in increasing order. %C A130228 Cf. A093788. %H A130228 Eric Angelini, <a href="/A130228/b130228.txt">Table of n, a(n) for n = 1..153</a> %H A130228 Gerard Schildberger, <a href="/A006968/a006968.txt">The first 3999 numbers in Roman numerals</a> %K A130228 base,easy,nonn %O A130228 1,2 %A A130228 _Eric Angelini_, Aug 05 2007