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 A160677 #10 Feb 17 2019 20:20:22
%S A160677 2,7,20,22,36,70,72,97,153,200,202,207,220,222,236,315,351,360,362,
%T A160677 379,448,653,700,702,707,720,722,736,871,970,972,997,1035,1087,1177,
%U A160677 1235,1267,1350,1352,1357,1386,1537,1677,1735,1767,1818,1836,1870,1872,1897
%N A160677 Numbers k such that k, 2k and 3k use the same number of characters when expressed in Roman numerals.
%C A160677 2 = II, 4 = IV, 6 = VI;
%C A160677 7 = VII, 14 = XIV, 21 = XXI;
%C A160677 20 = XX, 40 = XL, 60 = LX.
%H A160677 Nathaniel Johnston, <a href="/A160677/b160677.txt">Table of n, a(n) for n = 1..57</a> (complete up to 3999)
%p A160677 for n from 1 to 3999 do if(length(convert(n, roman)) = length(convert(2*n, roman)) and length(convert(n, roman)) = length(convert(3*n, roman)))then printf("%d, ", n): fi: od: # _Nathaniel Johnston_, May 18 2011
%Y A160677 Cf. A006968.
%K A160677 nonn,easy
%O A160677 1,1
%A A160677 _Claudio Meller_, May 23 2009, May 24 2009
%E A160677 Extended by _Nathaniel Johnston_, May 18 2011