A124675 a(n) = product of the positive integers k, k<= n, such that the positive integers <= k and coprime to k are also coprime to n.

1, 2, 6, 8, 120, 12, 5040, 384, 324, 80, 39916800, 144, 6227020800, 672, 90, 10321920, 355687428096000, 2592, 121645100408832000, 1600, 756, 84480, 25852016738884976640000, 62208, 9000000, 1198080, 14285134080, 18816

Offset: 1

Author

Leroy Quet, Dec 24 2006

Keywords

• nonn

Examples

			The positive integers k, k <= 6, where the positive integers <= k and coprime to k are also coprime to 6, are 1,2,6. So a(6) = 1*2*6 = 12.
		

Crossrefs

Cf. A126260, A124611.

Programs

Mathematica

f[n_] := Select[Range[n], GCD[ #, n] == 1 &];g[n_] := Select[Range[n], Times @@ GCD[f[ # ], n] == 1 &];Times @@@ Table[g[n], {n, 30}] (* Ray Chandler, Dec 24 2006 *)

Extensions

Extended by Ray Chandler, Dec 24 2006