A136952 Numbers k such that k and k^2 use only the digits 0, 4, 5, 7 and 9.

0, 7, 70, 97, 700, 970, 997, 7000, 9700, 9747, 9970, 9997, 70000, 70997, 75997, 97000, 97470, 99700, 99970, 99997, 700000, 709970, 709997, 759970, 759997, 970000, 974700, 997000, 999700, 999970, 999997, 7000000, 7050497, 7099700, 7099970, 7099997, 7450497, 7599700, 7599970, 7599997, 9700000, 9747000, 9970000, 9979757, 9997000

Offset

1,2

Comments

Generated with DrScheme.

Links

Jonathan Wellons, Table of n, a(n) for n = 1..599

J. Wellons, Tables of Shared Digits [archived]

Example

707075495050497^2 = 499955755700905407544579947009.

Mathematica

With[{c={0, 4, 5, 7, 9}}, Select[FromDigits/@Tuples[c, 7], SubsetQ[ c, IntegerDigits[ #^2]]&]] (* Harvey P. Dale, Nov 19 2019 *)

Crossrefs

Sequence in context: A204094 A061476 A136959 * A136960 A003363 A069542

Adjacent sequences: A136949 A136950 A136951 * A136953 A136954 A136955

Keyword

base,nonn

Author

Jonathan Wellons (wellons(AT)gmail.com), Jan 22 2008

Status

approved