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A186987 Number of subsets of {1, 2, ..., n} containing n and having <=3 pairwise coprime elements. 4
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified June 7 02:48 EDT 2020. Contains 334836 sequences. (Running on oeis4.)