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Numbers k such that k and k^2 use only the digits 0, 1, 2, 5 and 6.
1

%I #9 Jul 05 2021 02:55:31

%S 0,1,5,10,11,15,16,25,50,51,100,101,105,110,125,150,160,225,250,255,

%T 500,501,505,510,511,515,516,1000,1001,1005,1010,1011,1025,1050,1100,

%U 1101,1105,1125,1225,1250,1251,1265,1500,1505,1600,2250,2261,2500,2501,2550,5000,5001,5005,5010,5011,5015,5016,5025,5050,5051,5100,5101,5105,5110,5125,5150,5160

%N Numbers k such that k and k^2 use only the digits 0, 1, 2, 5 and 6.

%C Generated with DrScheme.

%H Jonathan Wellons, <a href="/A136823/b136823.txt">Table of n, a(n) for n = 1..1355</a>

%H Jonathan Wellons, <a href="https://web.archive.org/web/20090206165028/http://jonathanwellons.com/shared-digits/">Tables of Shared Digits</a>

%e 51202051^2 = 2621650026606601.

%Y Cf. A000290.

%K base,nonn

%O 1,3

%A Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008