[seqfan] Safe pseudoprimes to base 2

[Tomasz Ordowski]

Dear SeqFans,

I have an interesting conjecture:

For primes p > 7; if (p-1)/2 is prime, then (2^(p-1)-1)/3 is pseudoprime.

It seems that this pseudoprime is always a super-Poulet number.

How far can you check my guesses?

Best regards,

Thomas
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https://oeis.org/A005385
https://oeis.org/A001567
https://oeis.org/A050217
https://oeis.org/A178997