galois.prev_prime

galois.prev_prime(n: int) → int

Returns the nearest prime $p$ , such that $p \leq n$ .

Parameters:¶

n: int¶: An integer $n \geq 2$ .

Returns:¶

The nearest prime $p \leq n$ .

See also

primes, kth_prime, next_prime

Examples¶

In [1]: galois.prev_prime(13)
Out[1]: 13

In [2]: galois.prev_prime(15)
Out[2]: 13

In [3]: galois.prev_prime(6298891201241929548477199440981228280038)
Out[3]: 6298891201241929548477199440981228279991