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A325869
Number of maximal subsets of {1..n} containing n such that every pair of distinct elements has a different quotient.
9
1, 1, 1, 2, 3, 4, 6, 6, 6, 20, 32, 29, 57, 83, 113, 183, 373, 233, 549, 360
OFFSET
1,4
EXAMPLE
The a(1) = 1 through a(7) = 6 subsets:
{1} {1,2} {1,2,3} {1,3,4} {1,2,3,5} {1,2,5,6} {1,2,3,5,7}
{2,3,4} {1,3,4,5} {2,3,5,6} {1,2,5,6,7}
{2,3,4,5} {2,4,5,6} {2,3,4,5,7}
{1,3,4,5,6} {2,3,5,6,7}
{2,4,5,6,7}
{1,3,4,5,6,7}
MATHEMATICA
fasmax[y_]:=Complement[y, Union@@(Most[Subsets[#]]&)/@y];
Table[Length[fasmax[Select[Subsets[Range[n]], MemberQ[#, n]&&UnsameQ@@Divide@@@Subsets[#, {2}]&]]], {n, 10}]
KEYWORD
nonn,more
AUTHOR
Gus Wiseman, Jun 02 2019
STATUS
approved