A053929 Squares composed of digits {2,5,9}.

9, 25, 225, 529, 5929, 29929, 55225, 99225, 2295225, 5929225, 52229529, 552955225, 2952292225, 9559559529, 59299555225, 5929599995929, 9552259592929, 5255925929995225, 5555255292952225, 92922592295555529529, 959995929252599292299929255225, 5955252925229529299525595522529225

Offset: 1

Author

Patrick De Geest, Mar 15 2000

Keywords

• nonn
• base

Comments

a(n) == 5 or 9 (mod 10). - Chai Wah Wu, Nov 30 2018

Links

• Zhao Hui Du, Table of n, a(n) for n = 1..26
• Patrick De Geest, Squares containing at most three distinct digits, Index entries for related sequences.
• Hisanori Mishima, Sporadic tridigital solutions.
• Author?, Source, (txt)

Crossrefs

Cf. A053928.

Programs

Mathematica

Flatten[Table[Select[FromDigits /@ Tuples[{2, 5, 9}, n], IntegerQ[Sqrt[#]] &], {n, 6}]] (* Amiram Eldar, Nov 30 2018 *)

Formula

a(n) = A053928(n)^2. - Elmo R. Oliveira, Jul 16 2025

Extensions

One more term from C. Ronaldo (aga_new_ac(AT)hotmail.com), Jan 14 2005