OFFSET
0,4
COMMENTS
In other words, the elements are not disjoint from their own first differences.
FORMULA
a(n) = 2^n - A364463(n). - Chai Wah Wu, Sep 26 2023
EXAMPLE
The a(0) = 0 through a(5) = 14 subsets:
. . {1,2} {1,2} {1,2} {1,2}
{1,2,3} {2,4} {2,4}
{1,2,3} {1,2,3}
{1,2,4} {1,2,4}
{1,3,4} {1,2,5}
{1,2,3,4} {1,3,4}
{1,4,5}
{2,3,5}
{2,4,5}
{1,2,3,4}
{1,2,3,5}
{1,2,4,5}
{1,3,4,5}
{1,2,3,4,5}
MATHEMATICA
Table[Length[Select[Subsets[Range[n]], Intersection[#, Differences[#]]!={}&]], {n, 0, 10}]
PROG
(Python)
from itertools import combinations
def A364466(n): return sum(1 for l in range(n+1) for c in combinations(range(1, n+1), l) if not set(c).isdisjoint({c[i+1]-c[i] for i in range(l-1)})) # Chai Wah Wu, Sep 26 2023
CROSSREFS
The complement is counted by A364463.
KEYWORD
nonn
AUTHOR
Gus Wiseman, Jul 31 2023
EXTENSIONS
a(21)-a(32) from Chai Wah Wu, Sep 26 2023
a(33)-a(35) from Chai Wah Wu, Sep 27 2023
STATUS
approved