OFFSET
0,2
EXAMPLE
The a(0) = 1 through a(5) = 15 subsets:
{} {} {} {} {} {}
{1} {1} {1} {1} {1}
{2} {2} {2} {2}
{3} {3} {3}
{1,3} {4} {4}
{2,3} {1,3} {5}
{1,4} {1,3}
{2,3} {1,4}
{3,4} {1,5}
{2,3}
{2,5}
{3,4}
{3,5}
{4,5}
{3,4,5}
MATHEMATICA
Table[Length[Select[Subsets[Range[n]], Intersection[#, Join@@Table[Total/@Tuples[#, k], {k, 2, Length[#]}]]=={}&]], {n, 0, 10}]
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Gus Wiseman, Aug 15 2023
STATUS
approved