OFFSET
0,5
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.
LINKS
EXAMPLE
The a(0) = 0 through a(5) = 8 subsets:
. . . {1,2,3} {1,2,3} {1,2,3}
{1,2,3,4} {1,4,5}
{1,2,3,4}
{1,2,3,5}
{1,2,4,5}
{1,3,4,5}
{2,3,4,5}
{1,2,3,4,5}
MATHEMATICA
bpe[n_]:=Join@@Position[Reverse[IntegerDigits[n, 2]], 1];
Table[Length[Select[Subsets[Range[n]], Select[Tuples[bpe/@#], UnsameQ@@#&]=={}&]], {n, 0, 10}]
CROSSREFS
First differences are A370589.
The case without ones is A370643.
A070939 gives length of binary expansion.
A096111 gives product of binary indices.
A326031 gives weight of the set-system with BII-number n.
KEYWORD
nonn
AUTHOR
Gus Wiseman, Mar 08 2024
EXTENSIONS
a(21)-a(34) from Alois P. Heinz, Mar 09 2024
STATUS
approved