Notation of sets Solve this haha?

Question

solve this write the following in the form {x|p(x)};
A={3,4,5,10,11,12,13,14,15,16,17,18};
B={4,9,16,25};

Answer 1

B = { x | x = n^2, for n = 2,3,4, 5}

Answer 2

Your "description" of A is not sufficiently descriptive. Clearly, b = {n^2: 2 <= n <= 5}