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A186985 Number of 9-element subsets of {1, 2, ..., n} having pairwise coprime elements. 3
8, 8, 8, 8, 89, 90, 164, 168, 238, 244, 1300, 1301, 4941, 5734, 6132, 6379, 7000, 7089, 22019, 22975, 24637, 25150, 67393, 67678, 160771, 167602, 174367, 182152, 395833, 401344, 563893, 577192, 621709, 646954, 1280587, 1297318, 1442533, 1478536 (list; graph; refs; listen; history; text; internal format)
OFFSET

19,1

LINKS

Alois P. Heinz, Table of n, a(n) for n = 19..200

EXAMPLE

a(19) = 8 because there are 8 9-element subsets of {1, 2, ..., 19} having pairwise coprime elements: {1,3,4,5,7,11,13,17,19}, {1,3,5,7,8,11,13,17,19}, {1,3,5,7,11,13,16,17,19}, {1,2,3,5,7,11,13,17,19}, {1,4,5,7,9,11,13,17,19}, {1,2,5,7,9,11,13,17,19}, {1,5,7,8,9,11,13,17,19}, {1,5,7,9,11,13,16,17,19}.

CROSSREFS

Column 9 of triangle A186974. Partial sums of A186980.

Sequence in context: A166082 A145446 A248762 * A203127 A023415 A294659

Adjacent sequences:  A186982 A186983 A186984 * A186986 A186987 A186988

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Mar 02 2011

STATUS

approved

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Last modified September 18 11:20 EDT 2021. Contains 347518 sequences. (Running on oeis4.)