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A175236 Primes p such that 2^p+23 is also prime. 1
3, 7, 79, 359, 1031, 1039, 11311, 47599 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(9) > 5*10^5. - Robert Price, Sep 18 2015

LINKS

Table of n, a(n) for n=1..8.

FORMULA

A057203 INTERSECT A000040. [R. J. Mathar, Jul 06 2010]

EXAMPLE

For p=3, 2^3+23=31; p=7, 2^7+23=131; p=79, 2^79+23=604462909807314587353111

MATHEMATICA

Select[Prime[Range[1000]], PrimeQ[2^#+23]&] (*Robert Price, Sep 18 2015 *)

PROG

(Magma) [p: p in PrimesUpTo(1000) | IsPrime(2^p+23) ]

CROSSREFS

Sequence in context: A181554 A116294 A077793 * A343763 A045974 A001531

Adjacent sequences: A175233 A175234 A175235 * A175237 A175238 A175239

KEYWORD

nonn

AUTHOR

Vincenzo Librandi, Mar 09 2010

EXTENSIONS

Two more terms from R. J. Mathar, Jul 06 2010

a(7)-a(8) from Robert Price, Sep 18 2015

STATUS

approved

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Last modified November 30 12:40 EST 2022. Contains 358441 sequences. (Running on oeis4.)