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 A136863 Numbers k such that k and k^2 use only the digits 0, 1, 4 and 7. 0
 0, 1, 10, 100, 1000, 1071, 10000, 10710, 100000, 107100, 1000000, 1071000, 10000000, 10710000, 100000000, 107100000, 1000000000, 1071000000, 10000000000, 10710000000, 100000000000, 107100000000, 1000000000000, 1071000000000, 10000000000000, 10710000000000, 100000000000000, 107100000000000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Generated with DrScheme. LINKS Table of n, a(n) for n=1..28. J. Wellons, Tables of Shared Digits EXAMPLE 107100000000000^2 = 11470410000000000000000000000. MATHEMATICA With[{c={0, 1, 4, 7}}, Select[Flatten[FromDigits/@Tuples[c, 15]], SubsetQ[ c, IntegerDigits[ #^2]]&]] (* Harvey P. Dale, Feb 08 2023 *) CROSSREFS Sequence in context: A115798 A077439 A136839 * A031201 A228989 A072083 Adjacent sequences: A136860 A136861 A136862 * A136864 A136865 A136866 KEYWORD base,nonn AUTHOR Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008 STATUS approved

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Last modified September 26 17:04 EDT 2023. Contains 365665 sequences. (Running on oeis4.)