%I

%S 2,3,4,5,6,7,8,12,23,25,31,57,74,86,140,240,310,703,713,796,1028,1102

%N Numbers n such that 7*n!-1 is a prime.

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

%K nonn

%O 1,1

%A _Robert G. Wilson v_, Sep 13 2010