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Number of ordered triples of integers from [ 1,n ] with no common factors between pairs.
1

%I #15 Jul 13 2013 12:01:49

%S 1,2,4,6,12,14,26,33,46,52,84,91,137,152,174,199,279,295,397,425,475,

%T 513,663,692,819,876,986,1044,1286,1315,1593,1700,1838,1939,2123,2186,

%U 2582,2711,2905,3008,3498,3564,4106,4272,4476,4666,5316,5433,5985

%N Number of ordered triples of integers from [ 1,n ] with no common factors between pairs.

%H Reinhard Zumkeller, <a href="/A015632/b015632.txt">Table of n, a(n) for n = 1..500</a>

%F a(n) ~ k * n^3 where k is 1/6 * A065473 = 0.04779.... [_Charles R Greathouse IV_, Nov 14 2011]

%o (Haskell)

%o a015632 n = length [(x,y,z) | z <- [1..n], y <- [1..z], gcd y z == 1,

%o x <- [1..y], gcd x z == 1, gcd x y == 1]

%o -- _Reinhard Zumkeller_, Nov 14 2011

%K nonn

%O 1,2

%A _Olivier GĂ©rard_