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A186982 Number of 6-element subsets of {1, 2, ..., n} having pairwise coprime elements. 3
6, 6, 39, 41, 44, 56, 213, 219, 619, 655, 731, 777, 1853, 1909, 2775, 2961, 3707, 3923, 7803, 7859, 14308, 15876, 17437, 18459, 20865, 21313, 36080, 38103, 41568, 42828, 68688, 69360, 106470, 111456, 117033, 122883, 181854, 185066, 230208, 236610 (list; graph; refs; listen; history; text; internal format)
OFFSET

11,1

LINKS

Alois P. Heinz, Table of n, a(n) for n = 11..200

EXAMPLE

a(12) = 6 because there are 6 6-element subsets of {1, 2, ..., 12} having pairwise coprime elements: {1,2,3,5,7,11}, {1,5,7,8,9,11}, {1,4,5,7,9,11}, {1,3,5,7,8,11}, {1,3,4,5,7,11}, {1,2,5,7,9,11}.

CROSSREFS

Column 6 of triangle A186974. Partial sums of A186977.

Sequence in context: A203057 A165424 A244957 * A196075 A156099 A278435

Adjacent sequences:  A186979 A186980 A186981 * A186983 A186984 A186985

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Mar 02 2011

STATUS

approved

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Last modified January 17 19:58 EST 2019. Contains 319251 sequences. (Running on oeis4.)