"""
Created on May 23, 2014
@author: anuvrat
"""
from utils import prime_utils
LIMIT = 10000000
def check_condition(num):
t = prime_utils.totient(num)
return num * 1.0 / t if sorted(str(num)) == sorted(str(t)) else -1
primes = list(prime_utils.primesfrom2to(5000))
primes.reverse()
smallest_ratio = LIMIT
smallest_num = LIMIT
for a in primes:
max_allowed = LIMIT / a
for b in (i for i in primes if i <= max_allowed and i > 1000):
n = a * b
phi = n - a if a == b else n - (a + b) + 1
if not sorted(str(n)) == sorted(str(phi)):
continue
ratio = n * 1.0 / phi
if ratio < smallest_ratio:
'''
Created on Sep 28, 2012
@author: anuvrat
'''
from utils.prime_utils import totient, primesfrom2to
from utils.memoize import Memoize
@Memoize
def totient_chain_length( n ):
if n in range( 21 ): return ( 1, 1, 2, 3, 3, 4, 3, 4, 4, 4, 4, 5, 4, 5, 4, 5, 5, 6, 4, 5, 5 )[n]
return 1 + totient_chain_length( totient( n ) )
total = 0
for prime in primesfrom2to( 40000000 ):
if prime < 9000000: continue
if totient_chain_length( prime - 1 ) == 24: total += prime
print( total )
