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 A136986 #14 Apr 16 2024 13:55:46
%S A136986 1,2,11,12,21
%N A136986 Numbers k such that k and k^2 use only the digits 1, 2 and 4.
%C A136986 Sequence terminates.
%C A136986 Generated with DrScheme.
%H A136986 Jonathan Wellons, <a href="https://web.archive.org/web/20090206165028/http://jonathanwellons.com/shared-digits/">Tables of Shared Digits</a> [archived]
%e A136986 21^2 = 441.
%t A136986 Table[Select[(FromDigits/@Tuples[{1,2,4},d]),SubsetQ[{1,2,4},IntegerDigits[ #^2]]&],{d,2}]//Flatten (* _Harvey P. Dale_, Jan 10 2022 *)
%Y A136986 Cf. A137002.
%K A136986 base,fini,full,nonn
%O A136986 1,2
%A A136986 Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008