The Erdős-Nicolas-Sárközy conjecture concerns the number of nonempty admissible sets
contained in
. An admissible set
here requires that equal-sum subsets have equal cardinal
number. The conjecture asserts that
(Erdős et al. 1991), where
denotes big-Theta notation.
Wang and Yang (2026) proved that there are absolute constants such that
for every integer . The same bounds hold for the number of admissible
sets whose maximum is exactly
. The counting problem is distinct from maximizing the cardinal
number of an admissible set.