OFFSET
0,4
EXAMPLE
The a(1) = 1 through a(7) = 15 subsets:
{1} {2} {3} {4} {5} {6} {7}
{1,2,3} {1,4,5} {3,6} {1,6,7}
{2,3,5} {2,4,6} {2,5,7}
{3,4,5} {4,5,6} {3,4,7}
{1,2,3,4,5} {1,2,3,6} {3,5,7}
{1,3,5,6} {1,2,4,7}
{3,4,5,6} {2,3,6,7}
{1,2,3,4,6} {2,5,6,7}
{2,3,4,5,6} {3,5,6,7}
{1,2,5,6,7}
{1,3,4,5,7}
{1,3,4,6,7}
{2,3,4,5,7}
{2,4,5,6,7}
{1,2,3,4,5,6,7}
MATHEMATICA
Table[Length[Select[Subsets[Range[n], {1, n}], MemberQ[#, n]&&Divisible[Times@@#, Plus@@#]&]], {n, 0, 10}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Jun 13 2019
EXTENSIONS
a(21)-a(30) from Alois P. Heinz, Jun 13 2019
a(31)-a(40) from Bert Dobbelaere, Jun 23 2019
STATUS
approved