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%I #19 Jun 06 2022 12:24:34
%S 2,3,7,67
%N Primes p such that 2^p + 3 is prime.
%C The next term p is greater than 100000, corresponding to a prime 2^p + 3 with more than 30000 digits. - _Ryan Propper_, Aug 24 2005
%C Next term > 2205444. - _Joerg Arndt_, Mar 07 2021
%D J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 67, p. 24, Ellipses, Paris 2008.
%t Select[Prime[Range[20]],PrimeQ[2^#+3]&] (* _Harvey P. Dale_, Jun 06 2022 *)
%o (Python)
%o from sympy import isprime, primerange
%o def afind(limit):
%o for p in primerange(2, limit+1):
%o if isprime(2**p + 3): print(p, end=", ")
%o afind(1000) # _Michael S. Branicky_, Mar 07 2021
%Y Cf. A057737 (the corresponding primes).
%Y Subsequence of A057732.
%K more,nonn
%O 1,1
%A _G. L. Honaker, Jr._, Oct 29 2000
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