RosettaCodeData/Task/Pierpont-primes/Python/pierpont-primes.py
2023-07-01 13:44:08 -04:00

78 lines
1.8 KiB
Python

import random
# Copied from https://rosettacode.org/wiki/Miller-Rabin_primality_test#Python
def is_Prime(n):
"""
Miller-Rabin primality test.
A return value of False means n is certainly not prime. A return value of
True means n is very likely a prime.
"""
if n!=int(n):
return False
n=int(n)
#Miller-Rabin test for prime
if n==0 or n==1 or n==4 or n==6 or n==8 or n==9:
return False
if n==2 or n==3 or n==5 or n==7:
return True
s = 0
d = n-1
while d%2==0:
d>>=1
s+=1
assert(2**s * d == n-1)
def trial_composite(a):
if pow(a, d, n) == 1:
return False
for i in range(s):
if pow(a, 2**i * d, n) == n-1:
return False
return True
for i in range(8):#number of trials
a = random.randrange(2, n)
if trial_composite(a):
return False
return True
def pierpont(ulim, vlim, first):
p = 0
p2 = 1
p3 = 1
pp = []
for v in xrange(vlim):
for u in xrange(ulim):
p = p2 * p3
if first:
p = p + 1
else:
p = p - 1
if is_Prime(p):
pp.append(p)
p2 = p2 * 2
p3 = p3 * 3
p2 = 1
pp.sort()
return pp
def main():
print "First 50 Pierpont primes of the first kind:"
pp = pierpont(120, 80, True)
for i in xrange(50):
print "%8d " % pp[i],
if (i - 9) % 10 == 0:
print
print "First 50 Pierpont primes of the second kind:"
pp2 = pierpont(120, 80, False)
for i in xrange(50):
print "%8d " % pp2[i],
if (i - 9) % 10 == 0:
print
print "250th Pierpont prime of the first kind:", pp[249]
print "250th Pierpont prime of the second kind:", pp2[249]
main()