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A136860
Numbers k such that k and k^2 use only the digits 0, 1, 4, 6 and 7.
1
0, 1, 4, 10, 40, 100, 400, 1000, 1071, 4000, 7776, 10000, 10710, 10771, 40000, 77760, 100000, 106771, 106776, 107100, 107710, 400000, 777600, 1000000, 1007046, 1067710, 1067760, 1071000, 1077100, 1077776, 4000000, 6406771, 7771774, 7776000, 10000000, 10070460, 10677100, 10677600, 10710000, 10771000, 10777760, 40000000, 64067710
OFFSET
1,3
COMMENTS
Generated with DrScheme.
LINKS
Jonathan Wellons, Tables of Shared Digits
EXAMPLE
646076401416771^2 = 417414716467644616616040066441.
MATHEMATICA
With[{c={0, 1, 4, 6, 7}}, Select[FromDigits/@Tuples[c, 8], SubsetQ[ c, IntegerDigits[ #^2]]&]] (* Harvey P. Dale, Jul 16 2020 *)
CROSSREFS
Cf. A000290.
Sequence in context: A238721 A077811 A136855 * A136859 A051479 A149204
KEYWORD
base,nonn
AUTHOR
Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008
STATUS
approved