A053923 Squares composed of digits {2,4,6}.

4, 64, 4624, 26244, 446224, 26646244, 44462224, 662444644, 4444622224, 6266622244, 26646644644, 444446222224, 44444462222224, 64664242622464, 624666644462224, 4444444622222224, 444444446222222224, 44444444462222222224, 64266662664264424464, 4444444444622222222224

Offset: 1

Author

Patrick De Geest, Mar 15 2000

Keywords

• nonn
• base

Comments

Includes all numbers of the form (2*(10^k-1)/3 + 2)^2 for k >= 1. - Andrew Howroyd, Oct 18 2024

Links

• Zhao Hui Du, Table of n, a(n) for n = 1..47
• Patrick De Geest, Squares containing at most three distinct digits, Index entries for related sequences

Crossrefs

Cf. A053922.

Programs

Mathematica

Table[Select[FromDigits/@Tuples[{2,4,6},n],IntegerQ[Sqrt[#]]&],{n,10}]//Flatten (* The program generates the first 10 terms of the sequence.
To generate more, increase the "n" constant but the program may take a long time to run. *) (* Harvey P. Dale, Sep 25 2021 *)

Formula

a(n) = A053922(n)^2. - Andrew Howroyd, Oct 18 2024