def can_sqsum(n):
max_p = int(n/2)
max_p_if_prime = int(sqrt(n))
primes = primes_generator()
p = primes.next()
mult = 0
is_prime = True
while True:
if n % p == 0:
mult += 1
print n, "/", p
n /= p
if n == 1:
break
else:
if mult > 0:
if p % 4 == 3 and mult % 2 == 1:
return False
is_prime = False
p = primes.next()
#print p
mult = 0
if p > max_p or (is_prime and p > max_p_if_prime):
break
return True
#!/usr/bin/env python
from math import log10, ceil
import funcs
import string
max_set = 0
for p in funcs.primes_generator():
strp = str(p)
#print strp
for d in set( strp ):
primeset = []
digits = range(10)
if strp[-1] == d:
digits = range(1,10,2)
for d2 in digits:
if d == d2:
continue
p2 = string.replace( strp, d, str(d2) )
if p2[0] == '0':
continue
p2 = int(p2)
if funcs.is_prime( p2 ):
primeset.append(p2)
if len(primeset) > max_set:
max_set = len(primeset)
print "{0} {1} ---> {2}".format( max_set, p, primeset )
if max_set >= 8:
exit()
if p % 4 == 3 and mult % 2 == 1:
return False
is_prime = False
p = primes.next()
#print p
mult = 0
if p > max_p or (is_prime and p > max_p_if_prime):
break
return True
r = 10**10
rsq = r**2
print "pre-gen-primes"
max_p = r/2
for p in primes_generator():
if p >= max_p:
break
print p
print "done"
i = 0
while i < r:
slice_rsq = rsq - i**2
if sqrt(slice_rsq) % 1 == 0:
print slice_rsq
if can_sqsum( slice_rsq ):
print " Yes"
i+=1