Returns the nearest prime \(p\), such that \(p \le n\).
n (int) – An integer.
The nearest prime \(p \le n\). If \(n < 2\), the function returns None.
None
int
Examples
In [1]: galois.prev_prime(13) Out[1]: 13 In [2]: galois.prev_prime(15) Out[2]: 13