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 A356726 #26 Sep 11 2022 00:51:50
%S A356726 1,4,14,44,144,444,1444
%N A356726 Integers which have in Roman numerals more distinct symbols than any smaller number.
%C A356726 Indices of record highs in A057226.
%C A356726 Smallest number whose Roman notation has exactly n distinct symbols.
%C A356726 The sequence is finite because 1444 is the smallest number using the symbols I,V,X,L,C,D,M.
%e A356726 For n = 3, a(3) = 14 because 14 = XIV which is the smallest number with 3 symbols in Roman notation.
%t A356726 kmax=1500; a={}; n=1; For[k=1, k<=kmax, k++, If[Length[DeleteDuplicates[Characters[RomanNumeral[k]]]] == n, AppendTo[a, k]; n++; k=1]]; a (* _Stefano Spezia_, Aug 26 2022 *)
%Y A356726 Cf. A057226, A038378.
%K A356726 nonn,fini,full,easy
%O A356726 1,2
%A A356726 _Alain Cousquer_, Aug 24 2022