A187494 - OEIS

%I #9 Mar 09 2018 12:22:32

%S 1,1,3,3,5,5,9,12,21,27,41,46,74,99,137,153,203,307,414,464,612,788,

%T 1126,1292,1645,2039,2614,3291,4120,5127,6356,7180,9786

%N Number of 7-element nondividing subsets of {1, 2, ..., n}.

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

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/NondividingSet.html">Nondividing Set</a>

%e a(43) = 1 because there is one 7-element nondividing subset of {1,2,...,43}: {24,28,31,35,36,40,43}.

%Y Column 7 of triangle A187489. Cf. A068063.

%K nonn,more

%O 43,3

%A _Alois P. Heinz_, Mar 10 2011