A186984 Number of 8-element subsets of {1, 2, ..., n} having pairwise coprime elements.

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

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