OFFSET
1,2
COMMENTS
a(20) > 25000.
Corresponding primes are all verified prime (i.e., not probable prime): 2, 19, 163, 264539521, 9927882482918401, 141383412854531380076544001, ...
MATHEMATICA
Do[f=n!*3^n+1; If[PrimeQ[f], Print[{n, f}]], {n, 0, 25000}]
PROG
(PARI) isok(n) = isprime(n!*3^n + 1); \\ Michel Marcus, Jul 23 2017
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Robert Price, Jan 19 2014
EXTENSIONS
a(1)=0 prepended by Robert Price, Jul 22 2017
STATUS
approved