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Primes p such that q=(p^2+1)/2 is not a prime.
2

%I #10 Jun 12 2019 16:19:40

%S 2,7,13,17,23,31,37,41,43,47,53,67,73,83,89,97,103,107,109,113,127,

%T 137,149,151,157,163,167,173,179,191,193,197,211,223,227,229,233,239,

%U 241,251,257,263,269,277,281,283,293,307,311,313,317,331,337,347,353,359,367,373

%N Primes p such that q=(p^2+1)/2 is not a prime.

%H Ray Chandler, <a href="/A094516/b094516.txt">Table of n, a(n) for n = 1..10000</a>

%t Select[Prime[Range[100]],!PrimeQ[(#^2+1)/2]&] (* _Harvey P. Dale_, Apr 26 2017 *)

%Y Complement in primes of A048161.

%K nonn

%O 1,1

%A _N. J. A. Sloane_, following a suggestion by _R. K. Guy_, Jun 05 2004