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 A136912 Numbers k such that k and k^2 use only the digits 0, 2, 5, 6 and 7. 1

%I #11 Apr 12 2024 09:51:26

%S 0,5,25,26,50,75,76,225,250,255,260,265,266,275,500,505,525,526,725,

%T 726,750,755,760,775,2250,2500,2505,2550,2600,2650,2660,2750,2766,

%U 2775,5000,5005,5025,5026,5050,5075,5076,5250,5260,5265,7075,7225,7250,7260,7500,7525,7550,7600,7750,22500,25000,25005,25025,25050,25500,25505,26000,26005,26500

%N Numbers k such that k and k^2 use only the digits 0, 2, 5, 6 and 7.

%C Generated with DrScheme.

%H Jonathan Wellons, <a href="/A136912/b136912.txt">Table of n, a(n) for n = 1..1295</a>

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

%e 756706725^2 = 572605067660225625.

%t Select[FromDigits/@Tuples[{0,2,5,6,7},5],And@@Table[MemberQ[{0,2,5,6,7},n],{n,IntegerDigits[#^2]}]&] (* _Harvey P. Dale_, Nov 19 2013 *)

%t With[{c={0,2,5,6,7}},Select[FromDigits/@Tuples[c,5],SubsetQ[c,IntegerDigits[ #^2]]&]] (* _Harvey P. Dale_, Mar 14 2023 *)

%K base,nonn

%O 1,2

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

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Last modified July 23 18:51 EDT 2024. Contains 374553 sequences. (Running on oeis4.)