def solve():
even_char = re.compile("0|2|4|6|8")
sum_all = 0
count = 0
for i in primes_in_range(9,1000000,2):
s = str(i)
if '0' in s:
continue
# if even_char.search(s):
# continue
# else:
flag = True
for sub in truncl(s):
if not isprime(int(sub)):
flag = False
break
if flag:
for sub in truncr(s):
if not isprime(int(sub)):
flag = False
break
if flag:
count += 1
sum_all += i
print '*** PING *** ', i
print "Answer: first %i primes add up to %i" % (count, sum_all)
def solve_twodigit():
for n in xrange(99*99, 1, -1):
## if n < 9000:
## break
if ispalindrome(n) and not isprime(n):
# print 'checking',n
for x in factors(n):
if x <= 99 and x >= 10 and n / x > 10 and n / x < 99:
print n, ':', x, '*', n / x
break
def solve():
c = 0
for n in primes_in_range(2, 1000000, 1):
flag = True
for r in rots(n):
if not isprime(r):
flag = False
break
if flag:
c += 1
print "%i (%i)" % (n, c)
def solve():
n = 1
s = 0
start = time()
while n < 1000000:
# if n % 10000 == 0: print n,
if n%2 == 0 or n%3 == 0:
n+=1
continue
if isprime(n):
print n
s += n
n+=1
print s
print 'finished in %f seconds' % (time() - start)
"""
2007-12-16
By listing the first six prime numbers: 2, 3, 5, 7, 11, and 13, we
can see that the 6th prime is 13.
What is the 10001st prime number?
"""
import psyco
psyco.full()
from fast_prime import isprime
c = 0
n = 1
while c < 10001:
if isprime(n):
c += 1
n += 1
print n-1
e.g. |11| = 11 and |-4| = 4
Find the product of the coefficients, a and b, for the quadratic
expression that produces the maximum number of primes for consecutive
values of n, starting with n = 0.
"""
import psyco; psyco.full()
from fast_prime import isprime
##for n in range(80):
## res = n**2 + (-1000 * n) - 999
## print n, res, isprime(abs(res))
result = ((0, 0),0)
rng = 1000
for a in range(-rng,rng):
for b in range(-rng,rng):
n = 0
while isprime(abs(n**2 + (a * n) + b)):
n += 1
if n > result[1]:
result = (a, b), n
if a % 50 == 0: print a, result
print
print '==== FINAL ===='
print result
## ==== FINAL ====
## ((-61, 971), 71)
def check(n):
if not isprime(n): return 1
c = 1
while (((10 ** c) - 1) % n) != 0 and c < n:
c += 1
return c
"""
2007-12-14
The prime factors of 13195 are 5, 7, 13 and 29.
What is the largest prime factor of the number 317584931803?
>>> for x in factors(13195):
... if isprime(x):
... print '%i,'%x ,
5, 7, 13, 29,
"""
from fast_prime import factors, isprime
for x in factors(317584931803):
if isprime(x):
print "%i," % x,
# 1, 67, 829, 1459, 3919