OFFSET
0,6
COMMENTS
A pair of positive integers is divisible if the first divides the second, and is a binary containment if the positions of 1's in the reversed binary expansion of the first are a subset of the positions of 1's in the reversed binary expansion of the second.
FORMULA
a(n) = A325101(n) - n.
EXAMPLE
The a(3) = 1 through a(12) = 8 pairs:
{1,3} {1,3} {1,3} {1,3} {1,3} {1,3} {1,3} {1,3} {1,3} {1,3}
{1,5} {1,5} {1,5} {1,5} {1,5} {1,5} {1,5} {1,5}
{2,6} {1,7} {1,7} {1,7} {1,7} {1,7} {1,7}
{2,6} {2,6} {1,9} {1,9} {1,9} {1,9}
{2,6} {2,6} {2,6} {2,6}
{2,10} {1,11} {1,11}
{2,10} {2,10}
{4,12}
MATHEMATICA
Table[Length[Select[Subsets[Range[n], {2}], Divisible[#[[2]], #[[1]]]&&SubsetQ[Position[Reverse[IntegerDigits[#[[2]], 2]], 1], Position[Reverse[IntegerDigits[#1[[1]], 2]], 1]]&]], {n, 0, 30}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Mar 28 2019
STATUS
approved