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Least m>0 such that n!-m and n!!-m are relatively prime.
2

%I #4 Jul 29 2012 02:32:30

%S 2,1,1,1,2,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,

%T 1,1,1,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1,1,1,1,

%U 1,1,1,1,1,1,1,1,2,1,1,1,2,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1

%N Least m>0 such that n!-m and n!!-m are relatively prime.

%H Clark Kimberling, <a href="/A214710/b214710.txt">Table of n, a(n) for n = 1..1000</a>

%e gcd(45!-1,45!!-1) = 47, gcd(45!-2, 45!!-2) = 1, so a(45) = 2.

%t Table[m = 1; While[GCD[n! - m, n!! - m] != 1, m++]; m, {n, 1, 140}]

%Y Cf. A214711, the positions of 2 in A214710.

%K nonn,easy

%O 1,1

%A _Clark Kimberling_, Jul 27 2012