A187550 - OEIS

%I #8 Mar 09 2018 12:22:06

%S 2,3,4,5,6,9,12,15,19,24,35,46,60,83,102,135

%N Number of 8-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(65) = 2 because there are two 8-element nondividing subsets of {1,2,...,65}: {36,40,48,49,53,61,64,65}, {30,44,45,49,50,59,64,65}.

%Y Column 8 of triangle A187489. Cf. A068063.

%K nonn,more

%O 65,1

%A _Alois P. Heinz_, Mar 11 2011