login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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 * A045974 A001531 A219588

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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 21 10:00 EDT 2019. Contains 321368 sequences. (Running on oeis4.)