Solves problem 50

This means I know solveed 50 euler problems. Youhou !

README.markdown

@@ -62,6 +62,7 @@ So you may find some of the code here quite ugly. And this is the case :). Why o
 45 - Find the next triangle number that is also pentagonal and hexagonal. - < 1 sec <br />
 46 - What is the smallest odd composite that cannot be written as the sum of a prime and twice a square? - < 6 sec <br />
 48 - Find the last ten digits of 1^1 + 2^2 + ... + 1000^1000. - 0.053 <br />
+50 - Which prime, below one-million, can be written as the sum of the most consecutive primes? - **~= 1 hour** <br />
 52 - Find the smallest positive integer, x, such that 2x, 3x, 4x, 5x, and 6x, contain the same digits. - 2min <br />
 53 - How many values of C(n,r), for 1 <= n <= 100, exceed one-million? - < 1 sec <br />
 56 - Considering natural numbers of the form, a^b, finding the maximum digital sum. > 3 sec <br />
@@ -71,6 +72,7 @@ So you may find some of the code here quite ugly. And this is the case :). Why o
 
 43 - Find the sum of all pandigital numbers with an unusual sub-string divisibility property. <br />
 47 - Find the first four consecutive integers to have four distinct primes factors. <br />
+55 - How many Lychrel numbers are there below ten-thousand? <br />
 97 - Find the last ten digits of the non-Mersenne prime: 28433 <20> 2^7830457 + 1. <br />
 
 ## Contact

e_50.py

@@ -0,0 +1,60 @@
+#!/usr/bin/env python
+"""
+ ##---
+ # Julien Lengrand-Lambert
+ #Created on : 17 - 10 - 2012
+ #
+ # DESCRIPTION : Solves problem 50 of Project Euler
+The prime 41, can be written as the sum of six consecutive primes:
+
+41 = 2 + 3 + 5 + 7 + 11 + 13
+This is the longest sum of consecutive primes that adds
+to a prime below one-hundred.
+
+The longest sum of consecutive primes below one-thousand
+that adds to a prime, contains 21 terms, and is equal to 953.
+
+Which prime, below one-million, can be written as the sum of
+the most consecutive primes?
+ ##---
+ """
+import pickle
+
+# list of primes up to one million.
+plist = pickle.load(open("primes_list.dup", "rb"))
+
+
+def is_prime(val):
+    """
+    Returns True if the number is prime
+    """
+    return (val in plist)
+
+
+def sum_cons_primes(prime_list, max_val=1000000):
+    """
+    Returns the prime that can be written as the sum of
+    the most consecutive primes below one-million.
+    """
+    max_cons = 0
+    max_prime = 0
+    for el in prime_list:
+        if (prime_list.index(el)) % 10 == 0:
+            print "%d/%d" % (prime_list.index(el), len(prime_list))
+        cur_prime = el
+        cur_ind = prime_list.index(el)
+        nb_cons = 1
+        while cur_ind < len(prime_list) - 1 and cur_prime < max_val:
+            if is_prime(cur_prime):
+                if nb_cons > max_cons :
+                    max_cons = nb_cons
+                    max_prime = cur_prime
+
+            nb_cons += 1
+            cur_ind += 1
+            cur_prime += prime_list[cur_ind]
+
+    return max_prime, max_cons
+
+if __name__ == '__main__':
+    print "Answer : %d " % (sum_cons_primes(plist)[0])

e_55.py

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+#!/usr/bin/env python
+"""
+ ##---
+ # Julien Lengrand-Lambert
+ #Created on : 17 - 10 - 2012
+ #
+ # DESCRIPTION : Solves problem 55 of Project Euler
+If we take 47, reverse and add, 47 + 74 = 121, which is palindromic.
+
+Not all numbers produce palindromes so quickly. For example,
+
+349 + 943 = 1292,
+1292 + 2921 = 4213
+4213 + 3124 = 7337
+
+That is, 349 took three iterations to arrive at a palindrome.
+
+Although no one has proved it yet, it is thought that some numbers, like 196,
+never produce a palindrome.
+A number that never forms a palindrome through the reverse
+and add process is called a Lychrel number.
+Due to the theoretical nature of these numbers,
+and for the purpose of this problem, we shall assume that a number is Lychrel
+until proven otherwise.
+In addition you are given that for every number below ten-thousand,
+it will either (i) become a palindrome in less than fifty iterations,
+or, (ii) no one, with all the computing power that exists,
+has managed so far to map it to a palindrome.
+
+In fact, 10677 is the first number to be shown to require over fifty iterations
+before producing a palindrome: 4668731596684224866951378664
+(53 iterations, 28-digits).
+
+Surprisingly, there are palindromic numbers that are themselves Lychrel
+numbers; the first example is 4994.
+
+How many Lychrel numbers are there below ten-thousand?
+
+NOTE: Wording was modified slightly on 24 April 2007 to emphasise
+the theoretical nature of Lychrel numbers.
+ ##---
+ """
+
+
+if __name__ == '__main__':
+    print "Answer : %d " % (1)