A136865 Numbers k such that k and k^2 use only the digits 0, 1, 4, 7 and 9.

0, 1, 7, 10, 70, 97, 100, 107, 700, 701, 970, 997, 1000, 1007, 1049, 1070, 1071, 7000, 7001, 7010, 7071, 9700, 9701, 9970, 9997, 10000, 10007, 10070, 10097, 10490, 10700, 10710, 14107, 70000, 70001, 70010, 70100, 70107, 70499, 70710, 97000, 97001, 97010, 99700, 99970, 99997, 100000, 100007, 100070, 100097, 100499, 100700, 100970, 104900, 107000

Offset: 1

Author

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

Keywords

• base
• nonn

Comments

Generated with DrScheme.

Examples

			4140170401071^2 = 17141010949904404997947041.
		

Links

• Jonathan Wellons, Table of n, a(n) for n = 1..1020
• J. Wellons, Tables of Shared Digits [archived]

Programs

Mathematica

With[{c={0,1,4,7,9}},Select[FromDigits/@Tuples[c,6], SubsetQ[ c,IntegerDigits[ #^2]]&]] (* Harvey P. Dale, Aug 13 2020 *)