A136925 - OEIS

%I #9 Apr 12 2024 09:51:26

%S 0,27,270,297,2700,2970,2997,27000,28297,29700,29970,29997,88277,

%T 270000,282970,297000,298027,299700,299970,299997,882770,2700000,

%U 2787997,2829700,2970000,2980270,2997000,2999700,2999970,2999997,8827700,9888277,27000000,27879970,27980297,28297000,28299827,29700000,29802700,29970000,29997000

%N Numbers k such that k and k^2 use only the digits 0, 2, 7, 8 and 9.

%C Generated with DrScheme.

%H Jonathan Wellons, <a href="/A136925/b136925.txt">Table of n, a(n) for n = 1..406</a>

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

%e 879077927702027^2 = 772778002972890209208899908729.

%t With[{c={0,2,7,8,9}},Select[FromDigits/@Tuples[c,8],SubsetQ[c, IntegerDigits[#^2]]&]] (* _Harvey P. Dale_, Apr 27 2015 *)

%K base,nonn

%O 1,2

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