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A049496 a(n) and a(n)+4^k are primes at least for k=1,2,3,4,5,6. 2

%I

%S 37,163,15667,53593,142543,305407,607093,671353,904663,1172803,

%T 1233523,1351837,1378843,1389217,1457857,1686133,1842523,1867783,

%U 2451793,2668213,2694157,2979043,3095227,4228723,4890307,5535853,5772097,5859613,6404773,6827503,6933067

%N a(n) and a(n)+4^k are primes at least for k=1,2,3,4,5,6.

%e 37, 37+4=41, 37+16=53, 37+64=101, 37+256=293, 37+1024=1061, 37+4096=4133 are all primes; the smallest such a 7-chain is {37,41,53,101,293,1061,4133}.

%o (PARI) isok(n) = isprime(n) && isprime(n+4) && isprime(n+16) && isprime(n+64) && isprime(n+256) && isprime(n+1024) && isprime(n+4096); \\ _Michel Marcus_, Dec 22 2013

%Y Cf. A023200, A049492-A049495, A049497-A049500.

%K nonn

%O 1,1

%A _Labos Elemer_

%E More terms from _Michel Marcus_, Dec 22 2013

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Last modified August 12 23:19 EDT 2020. Contains 336440 sequences. (Running on oeis4.)