A214710 Least m>0 such that n!-m and n!!-m are relatively prime.

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, 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, 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

Offset

1,1

Links

Clark Kimberling, Table of n, a(n) for n = 1..1000

Example

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

Mathematica

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

Crossrefs

Cf. A214711, the positions of 2 in A214710.

Sequence in context: A054532 A260415 A370942 * A120888 A031230 A355032

Adjacent sequences: A214707 A214708 A214709 * A214711 A214712 A214713

Keyword

nonn,easy

Author

Clark Kimberling, Jul 27 2012

Status

approved