“…For a set A ⊆ N , let R 1 (A, n), R 2 (A, n) and R 3 (A, n) denote the numbers of solutions to a + a = n, a, a ∈ A, a + a = n, a, a ∈ A, a < a , a + a = n, a, a ∈ A, a a , respectively. For i ∈ {1, 2, 3}, Sárközy asked whether there are sets A and B with infinite symmetric difference such that R i (A, n) = R i (B, n) for all sufficiently large integers n. Dombi [3] proved that the answer is negative for i = 1 and positive for i = 2. For i = 3, Chen and Wang [2] proved that the set of nonnegative integers can be partitioned into two subsets A and B with R 3 (A, n) = R 3 (B, n) for all n n 0 .…”