Euler 60- Kind of a Monster Brute

gistfile1.txt

# set up prime sieve to n
n=10000
myPrimes = [True]*(n+1)
last = 0
for i in range (2,n):
	if myPrimes[i] == True:
		j = 2*i
		while j<=n:
			myPrimes[j]=False
			j=j+i	

def is_prime(n):
  if n == 2 or n == 3: return True
  if n < 2 or n%2 == 0: return False
  if n < 9: return True
  if n%3 == 0: return False
  r = int(n**.5)
  f = 5
  while f <= r:
    if n%f == 0: return False
    if n%(f+2) == 0: return False
    f +=6
  return True
 
def concatable(x,y):
	if is_prime(int(str(x)+str(y))) == True and is_prime(int(str(y)+str(x))) == True:
		return True	
 	else:
 		return False
 	
# dump sieve to list
primelist = []
for k in range (2,n):
	if myPrimes[k] == True:
		primelist.append(k)	

# general approach is start with a prime and keep adding concatables until you get 5
# i tried this with starts 3,5,7,11, and then 13- 13 was first to win
# it works in about 40s

start = 13
for p in range (primelist.index(start)+1,len(primelist)):
	list=[start]
	list.append(primelist[p])
	for l in range (primelist.index(start)+2,len(primelist)):
		for o in range (0, len(list)):
			if concatable(primelist[l],list[o])== False or primelist[l]<list[o]:
				break
			if concatable(primelist[l],list[o]) == True and o == len(list)-1:
				list.append(primelist[l])
	if len(list)==5:
		print list,sum(list)