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A295111 Primes p such that 2^p - p is also a prime. 0
2, 3, 13, 19, 481801 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(6) > 1061095.

Intersection of A000040 and A048744.

Since numbers other than 3 that are congruent to 3 mod 6 are composite, for n > 2, a(n) is congruent to 1 mod 6 (see comments by Iain Fox in A048744).

LINKS

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

EXAMPLE

p=13, 2^13 - 13 = 8179 is prime.

PROG

(PARI) lista(nn) = forprime(p=2, nn, if(ispseudoprime(2^p - p), print1(p, ", ")))

CROSSREFS

Cf. A000325, A081296, A048744, A057663, A057673.

Sequence in context: A234366 A084958 A249573 * A229117 A295722 A037392

Adjacent sequences:  A295108 A295109 A295110 * A295112 A295113 A295114

KEYWORD

hard,more,nonn

AUTHOR

Iain Fox, Nov 14 2017

STATUS

approved

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Last modified October 25 19:28 EDT 2020. Contains 338012 sequences. (Running on oeis4.)