OFFSET
1,3
COMMENTS
a(22) > 50000. - Roger Karpin, Nov 13 2016
EXAMPLE
k = 5 is here because 3*5! - 1 = 359 is prime.
MAPLE
for n from 0 to 1000 do if isprime(3*n! - 1) then print(n) end if end do;
MATHEMATICA
Select[Range[0, 10^3], PrimeQ[3 #! - 1] &] (* Robert Price, May 27 2019 *)
PROG
(PARI) isok(n) = isprime(3*n! - 1); \\ Michel Marcus, Nov 13 2016
(PFGW) ABC2 3*$a!+1
a: from 1 to 1000 // Jinyuan Wang, Feb 04 2020
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Phillip L. Poplin (plpoplin(AT)bellsouth.net), Oct 30 2002
EXTENSIONS
a(15)-a(21) from Roger Karpin, Nov 13 2016
STATUS
approved