A186988 Number of subsets of {1, 2, ..., n} containing n and having <=4 pairwise coprime elements.

1, 2, 4, 4, 12, 4, 26, 15, 29, 12, 84, 15, 137, 37, 55, 69, 279, 42, 397, 86, 162, 118, 663, 93, 546, 208, 468, 216, 1286, 93, 1593, 521, 651, 459, 914, 259, 2582, 648, 1025, 482, 3498, 288, 4106, 961, 1163, 1116, 5316, 641, 4326, 1033

Offset

1,2

Links

Alois P. Heinz, Table of n, a(n) for n = 1..1000

Example

a(5) = 12 because there are 12 subsets of {1,2,3,4,5} containing 5 and having <=4 pairwise coprime elements: {5}, {1,5}, {2,5}, {3,5}, {4,5}, {1,2,5}, {1,3,5}, {1,4,5}, {2,3,5}, {3,4,5}, {1,2,3,5}, {1,3,4,5}.

Crossrefs

Column 4 of triangle A186975. Sum of A186987 and A185348.

Sequence in context: A286714 A368436 A366616 * A186989 A186990 A186991

Adjacent sequences: A186985 A186986 A186987 * A186989 A186990 A186991

Keyword

nonn

Author

Alois P. Heinz, Mar 03 2011

Status

approved