def right_trunc(p):
if len(str(p)) > 1:
p //= 10
if is_prime(p):
return right_trunc(p)
else:
return False
else:
if is_prime(p) and p >= 2:
return True
def left_trunc(p):
tmp_str = str(p)
if len(tmp_str) > 1:
p = int(tmp_str[1:])
if is_prime(p):
return left_trunc(p)
else:
return False
else:
if is_prime(p) and p >= 2:
return True
def is_circular_prime(x):
s = str(x)
for i in range(len(s)):
rotation = s[i:] + s[:i]
if not is_prime(int(rotation)):
return False
return True
def permutations(val, perm_set, step = 0):
if step < len(val):
for i in range(step, len(val)):
# copy the string (store as array to swap indices)
perm_string = [c for c in val]
# swap the current index with the step
perm_string[step], perm_string[i] =perm_string[i], perm_string[step]
#rejoin into integer
term = int("".join(perm_string))
if is_prime(term):
perm_set.add(term)
# recurse on the portion of the string that has not been swapped yet
permutations(perm_string, perm_set, step + 1)
return perm_set
def prime_trunc(n):
if has_blocked_digits(n):
return False
elif is_prime(n):
if right_trunc(n):
return left_trunc(n)
return perm_set
def prime_perms(n):
my_seq = set()
perm_list = permutations(str(n), my_seq)
perm_list.remove(n)
for perm in perm_list:
b = perm + (perm - n)
if b in perm_list:
return [n, perm, b]
return []
#Driver code
if __name__ == '__main__':
start_time = time.time()
done = False
n = 999
seq = []
while not done:
n += 1
if not has_blocked_digits(n) and is_prime(n):
seq = prime_perms(n)
if len(seq) == 3 and 1487 not in seq:
done = True
print(''.join(map(str, seq)))
print("Runtime: {}".format(time.time() - start_time))
import time
import math
from problem27 import list_primes, is_prime
def gold_num(n):
prime_list = list_primes(n - 2)
is_gold_num = False
for k in range(1, int(math.sqrt(n / 2) + 1)):
p = n - 2 * k**2
if p in prime_list:
is_gold_num = True
break
return is_gold_num
# driver code
if __name__ == '__main__':
start_time = time.time()
done = False
n = 33
while not done:
n += 2
if not is_prime(n) and not gold_num(n):
done = True
print('Result: {}'.format(n))
print('Runtime: {}'.format(time.time() - start_time))