OFFSET
0,4
EXAMPLE
The a(2) = 1 through a(7) = 21 subsets:
{2} {2} {2} {2} {2} {2}
{3} {3} {3} {3} {3}
{4} {4} {4} {4}
{5} {5} {5}
{2,3,5} {6} {6}
{3,4,5} {3,6} {7}
{2,3,5} {3,6}
{2,4,6} {2,3,5}
{3,4,5} {2,4,6}
{4,5,6} {2,5,7}
{3,4,5,6} {3,4,5}
{2,3,4,5,6} {3,4,7}
{3,5,7}
{4,5,6}
{2,3,6,7}
{2,5,6,7}
{3,4,5,6}
{3,5,6,7}
{2,3,4,5,6}
{2,3,4,5,7}
{2,4,5,6,7}
MATHEMATICA
Table[Length[Select[Subsets[Range[2, n], {1, n}], Divisible[Times@@#, Plus@@#]&]], {n, 0, 10}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Jun 11 2019
EXTENSIONS
a(21)-a(29) from Alois P. Heinz, Jun 13 2019
a(30)-a(40) from Bert Dobbelaere, Jun 22 2019
STATUS
approved