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A180627 Numbers k such that 6*k! - 1 is prime. 10

%I

%S 0,1,2,5,8,42,318,326,1054,2987

%N Numbers k such that 6*k! - 1 is prime.

%C Tested to 4400. - _Robert G. Wilson v_, Sep 28 2010

%C a(11) > 6300. - _Jinyuan Wang_, Feb 04 2020

%H <a href="/index/Pri#primepop">Index entries for sequences related to numbers of primes of the form k*n!+-1</a>

%t fQ[n_] := PrimeQ[6 n! - 1]; k = 0; lst = {}; While[k < 1501, If[ fQ@k, AppendTo[lst, k]; Print@k]; k++ ]; lst

%o (PARI) is(k) = ispseudoprime(6*k!-1); \\ _Jinyuan Wang_, Feb 04 2020

%Y Cf. A002982, A076133, A076134, A099350, A099351, A180628, A180630, A180630, A180631.

%K nonn,more

%O 1,3

%A _Robert G. Wilson v_, Sep 13 2010

%E a(10) from _Robert G. Wilson v_, Sep 28 2010

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Last modified May 10 05:10 EDT 2021. Contains 343748 sequences. (Running on oeis4.)