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A049497 a(n) and a(n)+4^k are primes at least for k=1,2,3,4,5,6,7. 2
37, 163, 15667, 142543, 607093, 671353, 1457857, 2694157, 2979043, 4890307, 5772097, 6404773, 9139453, 10669003, 11170933, 11218747, 11905987, 13243063, 15130537, 18116473, 19433863, 21960577, 23524183, 25946083, 32380177, 45600157, 46960747, 51905137 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..28.

EXAMPLE

37, 37+4=41, 37+16=53, 37+64=101, 37+256=293, 37+1024=1061, 37+4096=4133, 37+16384=16421 are all primes; the smallest such a 8-chain of primes is {37,41,53,101,293,1061,4133,16421}.

PROG

(PARI) isok(n) = isprime(n) && isprime(n+4) && isprime(n+16) && isprime(n+64) && isprime(n+256) && isprime(n+1024) && isprime(n+4096) && isprime(n+16384); \\ Michel Marcus, Dec 22 2013

CROSSREFS

Cf. A023200, A049492-A049496, A049498-A049500.

Sequence in context: A269259 A269859 A049496 * A246842 A134219 A140593

Adjacent sequences:  A049494 A049495 A049496 * A049498 A049499 A049500

KEYWORD

nonn

AUTHOR

Labos Elemer

EXTENSIONS

More terms from Michel Marcus, Dec 22 2013

STATUS

approved

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Last modified March 23 12:43 EDT 2019. Contains 321430 sequences. (Running on oeis4.)