OFFSET
0,6
COMMENTS
A binary index of n is any position of a 1 in its reversed binary expansion. The binary indices of n are row n of A048793.
EXAMPLE
The a(0) = 0 through a(6) = 9 subsets:
. . . {1,2,3} {1,2,3} {1,2,3} {1,2,3}
{1,4,5} {1,4,5}
{2,3,4,5} {2,4,6}
{1,2,5,6}
{1,3,4,6}
{1,3,5,6}
{2,3,4,5}
{2,3,5,6}
{3,4,5,6}
MATHEMATICA
bpe[n_]:=Join@@Position[Reverse[IntegerDigits[n, 2]], 1];
fasmin[y_]:=Complement[y, Union@@Table[Union[s, #]& /@ Rest[Subsets[Complement[Union@@y, s]]], {s, y}]];
Table[Length[fasmin[Select[Subsets[Range[n]], Select[Tuples[bpe/@#], UnsameQ@@#&]=={}&]]], {n, 0, 10}]
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Gus Wiseman, Mar 10 2024
STATUS
approved