OFFSET
1,2
COMMENTS
a(6) > 25000, if it exists. - Giovanni Resta, Jun 01 2018
EXAMPLE
n=4, 2^4*4! + 4 + 1 = 389 is prime.
MATHEMATICA
Select[Range[100], PrimeQ[#! 2^# + # + 1] &] (* Giovanni Resta, May 31 2018 *)
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Labos Elemer, Feb 08 2000
EXTENSIONS
a(1)=0 inserted by Sean A. Irvine, Nov 03 2021
STATUS
approved