[seqfan] Re: finite a(n) for q=0 and infinite a(n) for q>0?
юрий герасимов
2stepan at rambler.ru
Thu Oct 25 18:19:55 CEST 2018
Dear SeqFans, another version on the same topic: (i) primes p such that
(2p-1)/k+2 is prime for all k where k is divisor of 2p-1. Or: 2, 3, 5, 23, 41,
89, 131, 359, ...(ii) a(n) is the number of some divisors q of n such that 2q+k
is prime for all k where k is divisor of 2n-1, or 0 is no such k exicts. Or: 1,
2, 2, 1, 2, 3, 0, 1, 2, 2, 0, 1, 0, 2, 2, 1, 0, 3, 0, 2, 3, 1, 1, 2, 1, 1, 2, 0,
0, 3, 0, 0, 2, 1, 0, 3, 0. 0. 1, 2, 1, 1, 0, 1, 1, 1, 0, 1, ...JSG.
More information about the SeqFan
mailing list