A186987 Number of subsets of {1, 2, ..., n} containing n and having <=3 pairwise coprime elements.

1, 2, 4, 4, 10, 4, 18, 11, 19, 10, 42, 11, 58, 21, 30, 33, 96, 22, 120, 36, 62, 48, 172, 37, 147, 69, 128, 70, 270, 37, 308, 123, 158, 117, 208, 75, 432, 147, 218, 119, 530, 78, 584, 186, 228, 212, 696, 133, 594, 191, 380, 256, 882, 166, 547

Offset

1,2

Links

Alois P. Heinz, Table of n, a(n) for n = 1..10000

Example

a(6) = 4 because there are 4 subsets of {1,2,3,4,5,6} containing 6 and having <=3 pairwise coprime elements: {6}, {1,6}, {5,6}, {1,5,6}.

Crossrefs

Column 3 of triangle A186975. Sum of A039649 and A185953 for n>1.

Sequence in context: A292302 A151712 A253827 * A300549 A038043 A126138

Adjacent sequences: A186984 A186985 A186986 * A186988 A186989 A186990

Keyword

nonn,look

Author

Alois P. Heinz, Mar 03 2011

Status

approved