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URL: https://oeis.org/A137117

⇱ A137117 - OEIS

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A137117
Numbers k such that k and k^2 use only the digits 2, 5, 7 and 9.
1
5, 27, 77, 527, 7227, 27797977
OFFSET
1,1
COMMENTS
Generated with DrScheme.
No further terms up to 10^12. - Harvey P. Dale, Oct 02 2017
No further terms up to 10^38. - Michael S. Branicky, May 27 2021
LINKS
EXAMPLE
27797977^2 = 772727525292529.
MATHEMATICA
With[{c={2, 5, 7, 9}}, Table[Select[FromDigits/@Tuples[c, n], SubsetQ[c, IntegerDigits[ #^2]]&], {n, 8}]]//Flatten (* Harvey P. Dale, Oct 02 2017 *)
PROG
(Python) # uses auptod in A137110
print(auptod(16, only="2579")) # Michael S. Branicky, May 27 2021
CROSSREFS
Sequence in context: A048712 A121876 A137116 * A064675 A135713 A085740
KEYWORD
base,nonn,more
AUTHOR
Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008
STATUS
approved