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A057678 Primes of the form 2^p - p where p is prime. 6
2, 5, 8179, 524269 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Next term, if it exists, has more than 618 digits. - Emeric Deutsch, Mar 27 2005

Next term, if it exists, has more than 10,000 digits.

The corresponding primes p are: 2, 3, 13, 19, .... - Gerasimov Sergey, Jul 26 2013

The corresponding 2^p - 1 are 3, 7, 8191, 524287 which are Mersenne primes (A000668).  Is this the case for all members of the sequence?  None of the other Mersenne primes < 2^132049-1 correspond to members of the sequence. - Robert Israel, Jul 18 2016

Next term is 2^481801-481801. 2^481801-1 is not a Mersenne prime. - Joerg Arndt, Jul 19 2016

LINKS

Table of n, a(n) for n=1..4.

EXAMPLE

p=3 is prime, and so is 2^p - p = 8 - 3 = 5, so 5 is in the sequence. - Michael B. Porter, Jul 19 2016

MAPLE

a:=proc(n) if isprime(2^ithprime(n)-ithprime(n))=true then 2^ithprime(n)-ithprime(n) else fi end: seq(a(n), n=1..310); # Emeric Deutsch

MATHEMATICA

lst={}; Do[p=Prime[n]; If[PrimeQ[p=2^p-p], AppendTo[lst, p]], {n, 5!}]; lst (* Vladimir Joseph Stephan Orlovsky, Jan 28 2009 *)

Select[Table[2^p-p, {p, Prime[Range[20]]}], PrimeQ] (* Harvey P. Dale, Sep 20 2018 *)

CROSSREFS

Cf. A000668, A057663, A057664, A057665, A056677.

Sequence in context: A187604 A082815 A115893 * A090071 A247148 A139062

Adjacent sequences:  A057675 A057676 A057677 * A057679 A057680 A057681

KEYWORD

nonn,more

AUTHOR

Labos Elemer, Oct 19 2000

STATUS

approved

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Last modified December 13 10:42 EST 2018. Contains 318086 sequences. (Running on oeis4.)