Question: Let L be a formal language over the alphabet = {a, b} such that L = the set of all strings that contains at least one a. Represent L by set builder notation.

The first few enumerated elements of L should be L = {a, aa, ab, ba, aaa, aab, aba, baa, bab, ...}. But I'm having difficulty representing this through set builder notation. My intuition was L = {aⁿb^m : n 1, m 0}, however, this enumerates L = {a, aab, aaabb, aaaabbb, ...}, which is wrong. Some help or hints would be appreciated. Thank you!