[seqfan] Re: Christmas puzzle: What is the next number in the sequence 2, 3, ...?

Rainer Rosenthal r.rosenthal at web.de
Fri Dec 25 11:44:29 CET 2009

mathstutoring schrieb:
> Consider the sequence of integers p for which p is prime and 2p-1 and 2p+1 are a pair of twin primes.
> Does anyone know what the next term is (if it exists it is greater than 2.5 x 10^9), or have a proof that the above sequence is complete?
> One to ponder after the Christmas turkey

Didn't you mean this one for April 1st?

Hint: three numbers in a row are not completely free from factor 3.


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