hermann on Wed, 06 Nov 2024 20:40:47 +0100


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Re: Game: find the integers 

On 2024-11-06 20:22, Bill Allombert wrote:

Dear PARI lovers,

A new little game!

Find positive integers n such that

2*eulerphi(n) = n+1

I know 8 solutions, but maybe there are more!

Cheers,
Bill.
Looking at the other 5 numbers found by GP, a 6th number with thinking below: 

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V



? n=65535*65537
4294967295
? 2*eulerphi(n)-n
1
?