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

Author

Alois P. Heinz, Mar 03 2011

Keywords

• nonn
• look

Examples

			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}.
		

Links

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

Crossrefs

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