A137098 Numbers k such that k and k^2 use only the digits 2, 4, 5, 7 and 9.

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

Jonathan Wellons, Table of n, a(n) for n = 1..319

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

Adjacent sequences: A137095 A137096 A137097 * A137099 A137100 A137101

Keyword

base,nonn,changed

Author

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

Status

approved