Distribution of residues modulo $p$ using the Dirichlet's class number formula

Let $p$ be an odd prime number. In this article, we study the number of quadratic residues and non-residues modulo $p$ which are multiples of $2$ or $3$ or $4$ and lying in the interval $[1,p-1]$, by applying the Dirichlet’s class number formula for the imaginary quadratic field $\mathbb{Q}(\sqrt{-p})$.