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A186984 Number of 8-element subsets of {1, 2, ..., n} having pairwise coprime elements. 3
8, 8, 73, 75, 79, 81, 420, 428, 719, 750, 1014, 1056, 3632, 3640, 10167, 11603, 12570, 13180, 14698, 14930, 36325, 38118, 41241, 42243, 92553, 93093, 186945, 195339, 203985, 213681, 401403, 407475, 549417, 563277, 608091, 633633, 1106226 (list; graph; refs; listen; history; text; internal format)
OFFSET

17,1

LINKS

Alois P. Heinz, Table of n, a(n) for n = 17..200

EXAMPLE

a(17) = 8 because there are 8 8-element subsets of {1, 2, ..., 17} having pairwise coprime elements: {1,2,3,5,7,11,13,17}, {1,2,5,7,9,11,13,17}, {1,3,4,5,7,11,13,17}, {1,3,5,7,8,11,13,17}, {1,3,5,7,11,13,16,17}, {1,4,5,7,9,11,13,17}, {1,5,7,9,11,13,16,17}, {1,5,7,8,9,11,13,17}.

CROSSREFS

Column 8 of triangle A186974. Partial sums of A186979.

Sequence in context: A020552 A272961 A117861 * A298962 A082798 A286068

Adjacent sequences:  A186981 A186982 A186983 * A186985 A186986 A186987

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Mar 02 2011

STATUS

approved

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Last modified January 22 18:06 EST 2019. Contains 319365 sequences. (Running on oeis4.)