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Numbers k such that k and k^2 use only the digits 1, 4, 7, 8 and 9.
1

%I #10 Feb 03 2025 09:39:25

%S 1,7,9,88,141,441,1191,4141,4471,8878,8941,9191,84779,87988,94191,

%T 97441,99471,118817,414417,847891,974417,989891,994479,4179891,

%U 4181488,4181971,9171417,9187917,9191191,9478817,9974417,9974878,11914191,44718988,84778817,84784891,91911478,91919471,94419141,99447417,848418988,884188878

%N Numbers k such that k and k^2 use only the digits 1, 4, 7, 8 and 9.

%C Generated with DrScheme.

%H Jonathan Wellons, <a href="/A137058/b137058.txt">Table of n, a(n) for n=1..205</a>

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

%e 894141979747891^2 = 799489879947477919191918947881

%K base,nonn

%O 1,2

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