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A180627
Numbers k such that 6*k! - 1 is prime.
10
0, 1, 2, 5, 8, 42, 318, 326, 1054, 2987, 11243
OFFSET
1,3
COMMENTS
Tested to 4400. - Robert G. Wilson v, Sep 28 2010
a(11) > 6300. - Jinyuan Wang, Feb 04 2020
MATHEMATICA
fQ[n_] := PrimeQ[6 n! - 1]; k = 0; lst = {}; While[k < 1501, If[ fQ@k, AppendTo[lst, k]; Print@k]; k++ ]; lst
PROG
(PARI) is(k) = ispseudoprime(6*k!-1); \\ Jinyuan Wang, Feb 04 2020
KEYWORD
nonn,more
AUTHOR
Robert G. Wilson v, Sep 13 2010
EXTENSIONS
a(10) from Robert G. Wilson v, Sep 28 2010
a(11) from Michael S. Branicky, Jul 04 2024
STATUS
approved