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A049493 Numbers n such that n and n+4^k are all primes for k=1,2,3. 3
3, 7, 37, 43, 67, 163, 757, 823, 967, 1087, 1213, 1303, 1423, 2293, 2377, 3187, 3343, 3847, 5653, 5923, 8677, 8803, 9157, 9277, 9787, 11257, 11617, 11923, 12097, 13693, 14653, 14767, 14827, 15667, 15733, 16417, 18127, 18397, 20113, 20743, 26293 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

3, 3+4=7, 3+16=19, 3+64=67 are all primes.

MATHEMATICA

Select[Prime[Range[3000]], And@@PrimeQ[#+4^{1, 2, 3}]&] (* Harvey P. Dale, Dec 26 2013 *)

PROG

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

CROSSREFS

Cf. A023200.

Sequence in context: A281093 A199347 A252795 * A260380 A260382 A260381

Adjacent sequences:  A049490 A049491 A049492 * A049494 A049495 A049496

KEYWORD

nonn

AUTHOR

Labos Elemer

STATUS

approved

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Last modified August 9 18:32 EDT 2020. Contains 336326 sequences. (Running on oeis4.)