

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.


0



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
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OFFSET

1,2


LINKS

Table of n, a(n) for n=1..28.


EXAMPLE

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.


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}] (*Chandler*)


CROSSREFS

Cf. A126260, A124611.
Sequence in context: A007849 A100621 A002176 * A279258 A120709 A002689
Adjacent sequences: A124672 A124673 A124674 * A124676 A124677 A124678


KEYWORD

nonn


AUTHOR

Leroy Quet, Dec 24 2006


EXTENSIONS

Extended by Ray Chandler, Dec 24 2006


STATUS

approved



