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A186988 Number of subsets of {1, 2, ..., n} containing n and having <=4 pairwise coprime elements. 4
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 (list; graph; refs; listen; history; text; internal format)
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: A242993 A263382 A286714 * A186989 A186990 A186991

Adjacent sequences:  A186985 A186986 A186987 * A186989 A186990 A186991

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Mar 03 2011

STATUS

approved

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Last modified September 28 04:51 EDT 2021. Contains 347703 sequences. (Running on oeis4.)