OFFSET
0,4
COMMENTS
Also the number of maximal subsets of {1..n} such that every orderless pair of (not necessarily distinct) elements has a different sum.
LINKS
Fausto A. C. Cariboni, Table of n, a(n) for n = 0..100
EXAMPLE
The a(0) = 1 through a(7) = 20 subsets:
{} {1} {1,2} {1,2} {2,3} {1,2,4} {1,2,4} {1,2,4}
{1,3} {1,2,4} {1,2,5} {1,2,5} {1,2,6}
{2,3} {1,3,4} {1,3,4} {1,2,6} {1,3,4}
{1,4,5} {1,3,4} {1,4,5}
{2,3,5} {1,3,6} {1,4,6}
{2,4,5} {1,4,5} {1,5,6}
{1,4,6} {2,3,5}
{1,5,6} {2,3,6}
{2,3,5} {2,3,7}
{2,3,6} {2,4,5}
{2,4,5} {2,4,7}
{2,5,6} {2,5,6}
{3,4,6} {2,6,7}
{3,5,6} {3,4,6}
{3,4,7}
{3,5,6}
{4,5,7}
{4,6,7}
{1,2,5,7}
{1,3,6,7}
MATHEMATICA
fasmax[y_]:=Complement[y, Union@@(Most[Subsets[#]]&/@y)];
Table[Length[fasmax[Select[Subsets[Range[n]], UnsameQ@@Subtract@@@Subsets[Union[#], {2}]&]]], {n, 0, 10}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Jun 02 2019
EXTENSIONS
a(21)-a(45) from Fausto A. C. Cariboni, Feb 08 2022
STATUS
approved