login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Primes p such that 2*p+1+A001414(p+1) is prime.
2

%I #8 Apr 14 2021 22:27:14

%S 3,17,31,59,83,97,113,127,131,257,263,379,433,479,491,563,571,619,643,

%T 701,727,811,853,883,919,937,983,1117,1187,1193,1249,1307,1459,1523,

%U 1627,1747,1777,1877,1987,2053,2207,2273,2293,2311,2423,2531,2609,2633,2683,2687,2719,2749,2789,2833,2927

%N Primes p such that 2*p+1+A001414(p+1) is prime.

%C Primes in A343412.

%C Includes 6*q-1 where q, 6*q-1 and 13*q+4 are prime; Dickson's conjecture implies there are infinitely many such q.

%H Robert Israel, <a href="/A343413/b343413.txt">Table of n, a(n) for n = 1..10000</a>

%e a(3) = 31 is a term because 2*31+1+A001414(31+1) = 73 is prime.

%p filter:= proc(p) local t; isprime(2*p+1+add(t[1]*t[2],t=ifactors(p+1)[2])) end proc:

%p select(filter, map(ithprime, [$1..1000]));

%Y Cf. A001414, A343412.

%K nonn

%O 1,1

%A _J. M. Bergot_ and _Robert Israel_, Apr 14 2021