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A057663 Primes p such that p + 2^p is also a prime. 4
3, 5, 89, 317, 701 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Different from A056206, where, e.g., at n=89, 89 is not minimal, A056206(89)=29 and not 89.

a(6) > 27479. - Ralf Stephan, Oct 23 2002

Intersection of A000040 and A052007. - Iain Fox, Nov 08 2017

a(6) > 678561. - Iain Fox, Nov 08 2017

Every term other than 3 is congruent to 5 (mod 6). - Arkadiusz Wesolowski, Nov 14 2017

LINKS

Table of n, a(n) for n=1..5.

EXAMPLE

q=3, 2^3 + 3 = 11 a prime.

MATHEMATICA

Select[Prime@ Range[10^3], PrimeQ[# + 2^#] &] (* Michael De Vlieger, Nov 08 2017 *)

PROG

(PARI) lista(nn) = forprime(p=3, nn, if(ispseudoprime(p + 2^p), print1(p, ", "))) \\ Iain Fox, Nov 13 2017

(MAGMA) [p: p in PrimesUpTo(1000) | IsPrime(2^p+p) ] // Vincenzo Librandi, Aug 07 2010

CROSSREFS

Cf. A006127, A056206, A056208, A057664, A057665.

Sequence in context: A133660 A271925 A236365 * A056244 A173487 A279310

Adjacent sequences:  A057660 A057661 A057662 * A057664 A057665 A057666

KEYWORD

nonn,hard,more

AUTHOR

Labos Elemer, Oct 16 2000

STATUS

approved

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Last modified January 22 12:13 EST 2019. Contains 319363 sequences. (Running on oeis4.)