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

Author

Alois P. Heinz, Mar 03 2011

Keywords

• nonn

Examples

			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}.
		

Links

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

Crossrefs

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