%I A131057
%S A131057 0,2,1,2,7,1,2,1,5,3,1,19,11,1,19,19,11,1,19,23,1,1,47,1,1,29,3,29,2,59,
%T A131057 73,1,43,1,13,17,41,1,2,5,3,53,79,7,1,53,23,1
%N A131057 Least nonnegative k such that n!-k is semiprime.
%C A131057 Semiprime analogue of A033933. After n = 3, a(n) is never again 0.
%F A131057 a(n) = MIN{k such that n!-k is in A001358 and k>=0}.
%e A131057 a(3) = 0 because 3! - 0 = 6 - 0 = 6 = 2 * 3.
%e A131057 a(4) = 2 because 4! - 2 = 24 - 2 = 22 = 2 * 11.
%e A131057 a(5) = 1 because 5! - 1 = 119 = 7 * 17.
%Y A131057 Cf. A001358, A033933.
%Y A131057 Sequence in context: A000139 A114572 A052621 this_sequence A051852 A054495 
               A007966
%Y A131057 Adjacent sequences: A131054 A131055 A131056 this_sequence A131058 A131059 
               A131060
%K A131057 easy,nonn
%O A131057 3,2
%A A131057 Jonathan Vos Post (jvospost3(AT)gmail.com), Sep 24 2007