Define $K$ the index set of $G=\left \{ 1,2,...,n \: |\:n\in \mathbb{N}_0,|G|\geq 100 \right \}$

Question

Lets define set G: $$G=\left \{ 1,2,...,n \: |\:n\in \mathbb{N}_0,|G|\geq 100 \right \}$$

How to define K its index set?

$$K=\left \{ ? \right \}$$