belph.py

#!/usr/bin/python3

# https://oeis.org/A232449
# Belphegor's Prime: n = 13


def belph(n):
    belph = (10 ** (n + 3) + (2 * 3 ** 2 * 37)) * 10 ** (n + 1) + 1
    return belph


# https://www.daniweb.com/programming/software-development/code/216880/check-if-a-number-is-a-prime-number-python
def is_prime(n):
    # make sure n is a positive integer
    n = abs(int(n))
    # 0 and 1 are not primes
    if n < 2:
        return False
    # 2 is the only even prime number
    if n == 2:
        return True
    # all other even numbers are not primes
    if not n & 1:
        return False
    # range starts with 3 and only needs to go up the squareroot of n
    # for all odd numbers
    for x in range(3, int(n ** 0.5) + 1, 2):
        if n % x == 0:
            return False
    return True


if __name__ == "__main__":
    a = [1, 2, 3, 5, 8, 13]
    for n in a:
        p = belph(n)
        if p == 1000000000000066600000000000001:
            z = "%s equals to %s and is Belphegor's prime" % (n, p)
            print(z)
        print(is_prime(p))