

A187491


Number of 4element nondividing subsets of {1, 2, ..., n}.


1



1, 2, 3, 6, 10, 21, 32, 49, 65, 101, 150, 224, 305, 413, 525, 707, 908, 1174, 1479, 1871, 2269, 2826, 3396, 4138, 4967, 5991, 6917, 8244, 9673, 11328, 12958, 15091, 17112, 19771, 22468, 25485, 28870, 32861, 36298, 40969, 45615, 51015
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OFFSET

10,2


COMMENTS

A set is called nondividing if no element divides the sum of any nonempty subset of the other elements.


LINKS

Table of n, a(n) for n=10..51.
Eric Weisstein's World of Mathematics, Nondividing Set


EXAMPLE

a(10) = 1 because there is one 4element nondividing subset of {1,2,...,10}: {6,7,9,10}.


CROSSREFS

Column 4 of triangle A187489. Cf. A068063.
Sequence in context: A047111 A106741 A068991 * A178852 A215067 A008928
Adjacent sequences: A187488 A187489 A187490 * A187492 A187493 A187494


KEYWORD

nonn


AUTHOR

Alois P. Heinz, Mar 10 2011


STATUS

approved



