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 A244954 #23 Feb 01 2024 15:46:07
%S A244954 1,4,3,4,10,12,28,40,9,10,121,12,13,28,30,112,85,36,247,40,84,352,253,
%T A244954 120,325,364,27,28,841,30,31,256,363,850,280,36,37,760,39,40,82,84,
%U A244954 3010,352,90,1012,94,336,2548,850,255,364,742,108,2200,112,741
%N A244954 Smallest positive multiple of n whose base-3 representation contains only 0's and 1's.
%H A244954 Harvey P. Dale, <a href="/A244954/b244954.txt">Table of n, a(n) for n = 1..1000</a>
%H A244954 Ed Pegg Jr., <a href="http://www.mathpuzzle.com/Binary.html">'Binary' Puzzle</a>
%H A244954 Eric M. Schmidt, <a href="/A004290/a004290_1.sage.txt">Sage code to compute this sequence</a> (use b=3)
%H A244954 Chai Wah Wu, <a href="http://www.jstor.org/stable/10.4169/amer.math.monthly.121.06.529">Pigeonholes and repunits</a>, Amer. Math. Monthly, 121 (2014), 529-533.
%t A244954 Module[{nn=10,b3},b3=Rest[FromDigits[#,3]&/@Tuples[{0,1},nn]];Table[SelectFirst[b3,Mod[ #,n]==0&],{n,60}]] (* _Harvey P. Dale_, Feb 01 2024 *)
%o A244954 (PARI) a(n,b=3) = if (n, k=1; while(vecmax(digits(k*n, b))>1, k++); k*n); \\ _Michel Marcus_, Jul 10 2014
%Y A244954 Cf. A004283 (written in base 3), A004290, A244955-A244960.
%K A244954 nonn,base
%O A244954 1,2
%A A244954 _Eric M. Schmidt_, Jul 09 2014
%E A244954 Data changed, offset changed, Mathematica program replaced, and b-file replaced by _Harvey P. Dale_, Feb 01 2024