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A015632
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Number of ordered triples of integers from [ 1,n ] with no common factors between pairs.
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1
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1, 2, 4, 6, 12, 14, 26, 33, 46, 52, 84, 91, 137, 152, 174, 199, 279, 295, 397, 425, 475, 513, 663, 692, 819, 876, 986, 1044, 1286, 1315, 1593, 1700, 1838, 1939, 2123, 2186, 2582, 2711, 2905, 3008, 3498, 3564, 4106, 4272, 4476, 4666, 5316, 5433, 5985
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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LINKS
| Reinhard Zumkeller, Table of n, a(n) for n = 1..500
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FORMULA
| a(n) ~ k * n^3 where k is 1/6 * A065473 = 0.04779.... [Charles R Greathouse IV, Nov 14 2011]
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PROG
| (Haskell)
a015632 n = length [(x, y, z) | z <- [1..n], y <- [1..z], gcd y z == 1,
x <- [1..y], gcd x z == 1, gcd x y == 1]
-- Reinhard Zumkeller, Nov 14 2011
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CROSSREFS
| Sequence in context: A061012 A161337 A050055 * A111084 A015636 A015663
Adjacent sequences: A015629 A015630 A015631 * A015633 A015634 A015635
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KEYWORD
| nonn
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AUTHOR
| Olivier Gerard (olivier.gerard(AT)gmail.com)
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