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A076134
Numbers k such that 3*k! - 1 is prime.
11
0, 1, 2, 3, 4, 5, 9, 12, 17, 26, 76, 379, 438, 1695, 6709, 13313, 18504, 19021, 24488, 45552, 49085
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
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