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%I #13 Nov 21 2017 20:00:12
%S 2,3,13,19,481801
%N Primes p such that 2^p - p is also a prime.
%C a(6) > 1061095.
%C Intersection of A000040 and A048744.
%C Since numbers other than 3 that are congruent to 3 mod 6 are composite, for n > 2, a(n) is congruent to 1 mod 6 (see comments by _Iain Fox_ in A048744).
%e p=13, 2^13 - 13 = 8179 is prime.
%o (PARI) lista(nn) = forprime(p=2, nn, if(ispseudoprime(2^p - p), print1(p, ", ")))
%Y Cf. A000325, A081296, A048744, A057663, A057673.
%K hard,more,nonn
%O 1,1
%A _Iain Fox_, Nov 14 2017
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