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 A178968 #12 Aug 20 2021 12:11:53
%S A178968 8,13,17,22,24,26,29,31,35,42,44,46,49,53,57,62,64,66,69,71,75,80,92,
%T A178968 94,96,99,103,107,112,114,116,119,121,125,130,141,145,152,154,156,159,
%U A178968 161,165,170,191,195,202,204,206,209,211,215,220,240,251,255,260
%N A178968 Numbers that are represented in Roman numerals by exactly four letters.
%H A178968 Nathaniel Johnston, <a href="/A178968/b178968.txt">Table of n, a(n) for n = 1..215</a> (complete up to 3999)
%p A178968 for n from 1 to 3999 do if(length(convert(n, roman)) = 4)then printf("%d, ", n): fi: od: # _Nathaniel Johnston_, May 18 2011
%t A178968 Select[Range[300],StringLength[RomanNumeral[#]]==4&] (* _Harvey P. Dale_, Aug 20 2021 *)
%Y A178968 Cf. A142958.
%K A178968 base,easy,nonn
%O A178968 1,1
%A A178968 _Kyle Stern_, Jan 01 2011
%E A178968 Extended by _Nathaniel Johnston_, May 18 2011