def __init__(self, n, primelist=None):
self.number = n
self.target = n
self.current = 2
if primelist:
self.primes = primelist
else:
prime = sieve(n)
self.primes = [x for x in xrange(n) if prime[x]]
self.primeIter = ifilter(None, self.primes)
from sievebool import sieve
prime = sieve(1000000)
primes = [x for x in xrange(len(prime)) if prime[x]]
def primefactors(n):
if n in primes:
return {n: 1}
factors = {}
target = n
for x in primes:
if x > target:
break
mult = 0
if not n % x:
while not n % x:
mult += 1
n /= x
factors[x] = mult
return factors
from sievebool import sieve
primes = sieve(1000000)
primes = set([x for x in xrange(len(primes)) if primes[x]])
def lenseries(a, b):
if b not in primes: return 0
count = 0
while (True):
if count**2 + a*count + b not in primes: break
count += 1
return count
maxlength = 0
prod = 0
for a in xrange(-999, 1000):
for b in xrange(-999, 1000):
length = lenseries(a, b)
if length > maxlength:
maxlength = length
prod = a * b
print prod
from sievebool import sieve
print "Building primes..."
primes = sieve(1000000)
primelist = []
for x in xrange(len(primes)):
if primes[x]:
primelist.append(x)
def istruncatableL(n):
n = str(n)[1:]
while n:
if not primes[int(n)]:
return False
n = n[1:]
return True
def istruncatableR(n):
n /= 10
while n > 0:
if not primes[n]:
return False
n /= 10
return True
count = 0
total = 0
print "Testing..."
for x in primelist:
if istruncatableL(x) and istruncatableR(x):
from sievebool import sieve
prime = sieve(1000000)
primes = [x for x in xrange(len(prime)) if prime[x]]
def primefactorset(n):
factors = set()
for x in primes:
if x > n / 2:
break
if not n % x:
factors.add(x)
return factors
def istheanswer(x):
if len(primefactorset(x)) != 4:
return False
if len(primefactorset(x + 1)) != 4:
return False
if len(primefactorset(x + 2)) != 4:
return False
if len(primefactorset(x + 3)) != 4:
return False
return True
x = 1
while not istheanswer(x):
x += 1