Let $s \in \mathbb{N}$ be some positive integer: How many combinations for $v \in \mathbb{N_0}^d$ so that $\sum^d_{j=1} v^2_{j} < s$

Question

I have a combinatorial problem. I want to find out how many possible combinations exists for a vector $v \in \mathbb{N_0}^d$ so that the squared $l_2$ norm is smaller than some positive integer value $s$.

Problem:

Let $s \in \mathbb{N}$ be some positive integer. Let $V = \{v \in \mathbb{N_0}^d | \sum^d_{j=1} v^2_{j} < s\}$. What is $|V|$.