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A136865
Numbers k such that k and k^2 use only the digits 0, 1, 4, 7 and 9.
2
0, 1, 7, 10, 70, 97, 100, 107, 700, 701, 970, 997, 1000, 1007, 1049, 1070, 1071, 7000, 7001, 7010, 7071, 9700, 9701, 9970, 9997, 10000, 10007, 10070, 10097, 10490, 10700, 10710, 14107, 70000, 70001, 70010, 70100, 70107, 70499, 70710, 97000, 97001, 97010, 99700, 99970, 99997, 100000, 100007, 100070, 100097, 100499, 100700, 100970, 104900, 107000
OFFSET
1,3
COMMENTS
Generated with DrScheme.
LINKS
J. Wellons, Tables of Shared Digits [archived]
EXAMPLE
4140170401071^2 = 17141010949904404997947041.
MATHEMATICA
With[{c={0, 1, 4, 7, 9}}, Select[FromDigits/@Tuples[c, 6], SubsetQ[ c, IntegerDigits[ #^2]]&]] (* Harvey P. Dale, Aug 13 2020 *)
CROSSREFS
Sequence in context: A187999 A097187 A115904 * A350533 A351685 A123797
KEYWORD
base,nonn
AUTHOR
Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008
STATUS
approved