A note on a special case of the Frobenius problem

For a set of positive and relative prime integers A = {a ₁…,a _k }, let Γ(A) denote the set of integers of the form a ₁ x ₁+…+a _k x _k with each x _j ≥ 0. Let g(A) (respectively, n(A) and s(A)) denote the largest integer (respectively, the number of integers and sum of integers) not in Γ(A). Let S*(A) denote the set of all positive integers n not in Γ(A) such that n + Γ(A) \ {0} ? Γ((A)\{0}. We determine g(A), n(A), s(A), and S*(A) when A = {a, b, c} with a | (b + c).