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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
OFFSET
17,1
LINKS
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
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Mar 02 2011
STATUS
approved