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

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A057188 Numbers n such that (22^n+1)/23 is a prime. 14
3, 5, 13, 43, 79, 101, 107, 227, 353, 7393, 50287 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Some of the larger terms may only correspond to probable primes.

a(12) > 10^5 - Robert Price, Jun 02 2013

LINKS

Table of n, a(n) for n=1..11.

H. Dubner and T. Granlund, Primes of the Form (b^n+1)/(b+1), J. Integer Sequences, 3 (2000), #P00.2.7.

PROG

(PARI) isok(n) = (denominator(p=(22^n+1)/23)==1) && isprime(p); \\ Michel Marcus, Oct 30 2017

CROSSREFS

Sequence in context: A259932 A178432 A236068 * A128548 A321358 A113606

Adjacent sequences:  A057185 A057186 A057187 * A057189 A057190 A057191

KEYWORD

nonn,more

AUTHOR

N. J. A. Sloane, Sep 15 2000

EXTENSIONS

a(11) from Robert Price, Jun 02 2013

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 December 14 22:42 EST 2019. Contains 329987 sequences. (Running on oeis4.)