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!)
A139066 Primes of the form (8+k!)/8. 42
631, 45361, 453601, 59875201, 10897286401, 304112751022080001, 3231502092360622080001, 77556050216654929920001, 1105220249217462744317952000001, 332283946848556096005453226376826986289954816000000001 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Numbers k for which (8+k!)/8 is prime see A151913

The next term (a(11)) has 174 digits. - Harvey P. Dale, May 10 2016

LINKS

Table of n, a(n) for n=1..10.

MATHEMATICA

a = {}; Do[If[PrimeQ[(n! + 8)/8], AppendTo[a, (n! + 8)/8]], {n, 1, 50}]; a

Select[(8+Range[50]!)/8, PrimeQ] (* Harvey P. Dale, May 10 2016 *)

PROG

(PARI) for(k=4, 1e3, if(ispseudoprime(t=k!/8+1), print1(t", "))) \\ Charles R Greathouse IV, Jul 15 2011

CROSSREFS

Cf. A082672, A089085, A089130, A117141, A007749, A139056, A139057, A139058, A139059, A139060, A139061, A139061, A139062, A139063, A139064, A139065, A139066, A020458.

Sequence in context: A252412 A002227 A251217 * A186898 A006913 A154088

Adjacent sequences:  A139063 A139064 A139065 * A139067 A139068 A139069

KEYWORD

nonn

AUTHOR

Artur Jasinski, Apr 07 2008

EXTENSIONS

Corrected link to sequence of indexes. - Serge Batalov, Feb 17 2015

One more term (a(10)) added by Harvey P. Dale, May 10 2016

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 13 01:23 EST 2019. Contains 329963 sequences. (Running on oeis4.)