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Primes p == 5 (mod 6) that are not Sophie Germain primes.
1

%I #25 Oct 05 2016 15:21:38

%S 17,47,59,71,101,107,137,149,167,197,227,257,263,269,311,317,347,353,

%T 383,389,401,449,461,467,479,503,521,557,563,569,587,599,617,647,677,

%U 701,773,797,821,827,839,857,863,881,887,929,941,947,971,977,983,1061,1091,1097

%N Primes p == 5 (mod 6) that are not Sophie Germain primes.

%F Subset of A156543 and subset of A045979

%F Intersection of A007528 and A053176. - _Felix Fröhlich_, Aug 08 2016

%t Select[Prime[Range[150]], Mod[#, 6] == 5 && \[Not] PrimeQ[2 # + 1] &]

%o (PARI) forprime(p=1, 900, if(Mod(p, 6)==5 && !ispseudoprime(2*p+1), print1(p, ", "))) \\ _Felix Fröhlich_, Aug 08 2016

%Y Cf. A005384, A007528, A045979, A053176, A156543.

%K nonn

%O 1,1

%A _Hilko Koning_, Aug 08 2016