rule is here.
Primes of the form x2 + ny2.
p = . (2020)
p = 4k + 1, p = 8k + 1 / 8k + 3, p = 3k + 1, p = 20k + 1 / 20k + 9, p = 24k + 1 / 24k + 7, p = 7k + 1 / 7k + 2 / 7k + 4, p = 40k + 1 / 40k + 9 / 40k + 11 / 40k + 19.
p = . (2020)
p = 4k + 1, p = 8k + 1 / 8k + 3, p = 3k + 1, p = 20k + 1 / 20k + 9, p = 24k + 1 / 24k + 7, p = 7k + 1 / 7k + 2 / 7k + 4, p = 40k + 1 / 40k + 9 / 40k + 11 / 40k + 19.