[seqfan] Question on primes
Creighton Kenneth Dement
creighton.k.dement at mail.uni-oldenburg.de
Wed Jun 10 09:24:30 CEST 2009
I have a quick question that is probably either trivial or really hard.
Observe that (2 + 1)(13 - 1) = 36 is a square. 2 and 13 are primes, but
they are not consecutive (i.e. there are other primes inbetween).
If p and q are consecutive primes, do we have
(p + 1)*(q - 1) is a square if and only if q = p + 2, i.e. p and q are
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