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%I #9 Jan 22 2018 21:09:20
%S 7,37,163,757,967,1303,2293,2377,8677,8803,9157,9277,14827,15667,
%T 16417,20113,27763,29863,41953,53593,56527,56893,61027,67153,69763,
%U 74827,79333,83203,90007,95467,111577,129277,135193,137383,142543,151783
%N a(n) and a(n)+4^k are primes at least for k=1,2,3,4.
%H Harvey P. Dale, <a href="/A049494/b049494.txt">Table of n, a(n) for n = 1..1000</a>
%e 7,7+4=11,7+16=23,7+64=71,7+256=263 are all primes: it is the smallest such quintet.
%t Select[Prime[Range[15000]],AllTrue[#+{4,16,64,256},PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Jan 22 2018 *)
%o (PARI) isok(n) = isprime(n) && isprime(n+4) && isprime(n+4^2) && isprime(n+4^3) && isprime(n+4^4); \\ _Michel Marcus_, Dec 31 2013
%Y Cf. A023200, A049492, A049493, A049495-A049500.
%K nonn
%O 1,1
%A _Labos Elemer_
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