perplexus.info :: Numbers : Only prime digits allowed

Only prime digits allowed (Posted on 2019-01-31)

List all the integers containing only prime-digits such that their squares also contain prime-digits only.

Hint: The highest qualifying number is below 77777.

Source: Claudio Meller's site.

Submitted by Ady TZIDON

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Solution: (Hide)

Claudio states that apparently the only integers having such property are: 5, 235 & 72335.
oeis A153025

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Subject	Author	Date
Puzzle Solution	K Sengupta	2022-06-08 00:04:23
computer solution	Charlie	2019-01-31 15:57:31

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