A139066 Primes of the form (8+k!)/8.

631, 45361, 453601, 59875201, 10897286401, 304112751022080001, 3231502092360622080001, 77556050216654929920001, 1105220249217462744317952000001, 332283946848556096005453226376826986289954816000000001

Offset: 1

Author

Artur Jasinski, Apr 07 2008

Keywords

• nonn

Comments

For 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

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

Crossrefs

Cf. A020458, A082672, A089085, A089130, A117141, A007749, A139056, A139057, A139058, A139059, A139060, A139061, A139062, A139063, A139064, A139065, A139155, A151913.

Programs

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 *)

PARI

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

Formula

a(n) = A139155(A151913(n)). - Amiram Eldar, Oct 14 2024

Extensions

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

a(10) from Harvey P. Dale, May 10 2016