Item 0.3.2.c.

This is the set \(\{1, 2, 5, 10, \ldots\}\text{,}\) namely the set of numbers that are the result of squaring and adding 1 to a natural number. (\(0^2 + 1 = 1\text{,}\) \(1^2 + 1 = 2\text{,}\) \(2^2 + 1 = 5\) and so on.) Thus the least element of the set is 1.