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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
37, 163, 15667, 53593, 142543, 305407, 607093, 671353, 904663, 1172803, 1233523, 1351837, 1378843, 1389217, 1457857, 1686133, 1842523, 1867783, 2451793, 2668213, 2694157, 2979043, 3095227, 4228723, 4890307, 5535853, 5772097, 5859613, 6404773, 6827503, 6933067 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..31.

EXAMPLE

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}.

PROG

(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

CROSSREFS

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

Sequence in context: A142909 A269259 A269859 * A049497 A246842 A134219

Adjacent sequences:  A049493 A049494 A049495 * A049497 A049498 A049499

KEYWORD

nonn

AUTHOR

Labos Elemer

EXTENSIONS

More terms from Michel Marcus, Dec 22 2013

STATUS

approved

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Last modified March 21 01:18 EDT 2019. Contains 321356 sequences. (Running on oeis4.)