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%I #15 Jul 04 2021 19:20:38
%S 0,1,2,10,11,12,20,21,100,101,102,110,120,200,201,210,421,1000,1001,
%T 1002,1010,1011,1012,1020,1021,1071,1100,1101,1102,1200,1201,2000,
%U 2001,2010,2011,2100,2101,4210,10000,10001,10002,10010,10011,10012,10020,10021,10100,10110,10120,10200,10210,10710,11000,11001,11002,11010,11011,11020,12000
%N Numbers k such that k and k^2 use only the digits 0, 1, 2, 4 and 7.
%C Generated with DrScheme.
%H Jonathan Wellons, <a href="/A136819/b136819.txt">Table of n, a(n) for n = 1..1154</a>
%H J. Wellons, <a href="https://web.archive.org/web/20090206165028/http://jonathanwellons.com/shared-digits/">Tables of Shared Digits</a>
%e 4702140701^2 = 22110127172000771401.
%t With[{c={0,1,2,4,7}},Select[Union[Flatten[FromDigits/@Tuples[c,5]]], SubsetQ[ c, IntegerDigits[ #^2]]&]] (* _Harvey P. Dale_, Mar 24 2018 *)
%K base,nonn
%O 1,3
%A Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008
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