A136970 Numbers k such that k and k^2 use only the digits 1, 2, 3, 4 and 7.

1, 2, 11, 12, 21, 111, 132, 271, 421, 1111, 1171, 1312, 1332, 2171, 13332, 34311, 34312, 133332, 371111, 417412, 421111, 473421, 1214171, 1333332, 3337271, 3427421, 12137271, 13333332, 121337271, 131423412, 133333332, 177232171, 217433311, 333432412, 334232171, 337227421, 377774171, 473743311, 1114142412, 1114142421, 1114144171

Offset

1,2

Comments

Generated with DrScheme.

Links

Jonathan Wellons, Table of n, a(n) for n = 1..149

J. Wellons, Tables of Shared Digits [archived]

Example

217134132142421^2 = 47147231341242344447427741241.

Mathematica

Table[With[{c={1, 2, 3, 4, 7}}, Select[FromDigits/@Tuples[c, n], SubsetQ[ c, IntegerDigits[ #^2]]&]], {n, 10}]//Flatten (* Harvey P. Dale, Feb 24 2016 *) (* Harvey P. Dale, Feb 24 2016 *)

Crossrefs

Sequence in context: A038113 A089600 A114034 * A136967 A213975 A137001

Adjacent sequences: A136967 A136968 A136969 * A136971 A136972 A136973

Keyword

base,nonn

Author

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

Status

approved