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A137098
Numbers k such that k and k^2 use only the digits 2, 4, 5, 7 and 9.
1
2, 5, 7, 27, 77, 477, 527, 977, 2227, 5477, 7227, 7277, 22977, 49727, 49777, 54277, 97977, 99727, 99777, 229727, 274727, 495477, 499227, 499277, 724727, 774227, 2792477, 4945477, 4952227, 4957277, 4994777, 5224227, 5224727, 7244277, 7597977, 22299227, 22299277, 22924277, 27299227, 27797977, 47725527, 47955477, 49294277, 49452227, 49957227
OFFSET
1,1
COMMENTS
Generated with DrScheme.
Conjecture: the last digit of all terms except the first two is 7. - Harvey P. Dale, Jan 18 2016
LINKS
J. Wellons, Tables of Shared Digits [archived]
EXAMPLE
724722429592527^2 = 525222599954495254727254245729.
MATHEMATICA
With[{c={2, 4, 5, 7, 9}}, Flatten[Table[Select[FromDigits/@Tuples[ c, n], SubsetQ[ c, IntegerDigits[#^2]]&], {n, 8}]]] (* Harvey P. Dale, Jan 18 2016 *)
CROSSREFS
Sequence in context: A071898 A002317 A343596 * A082013 A171831 A192560
KEYWORD
base,nonn
AUTHOR
Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008
STATUS
approved