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?


This is my solution:

from datetime import datetime

candidates = []

def reverse(number):
    ''' Returns the reverse order of an integer,
        for example: reverse(123) returns the integer 321 '''
    number = str(number)
    return int(number[::-1])

def is_lychrel(number):
    ''' Returns True if 'number' is a lychrel candidate,
        but works only with numbers from 1 to 10000 '''
    iterated = number + reverse(number)
    for i in range(25):
        rev_iterated = reverse(iterated)
        if iterated != rev_iterated:
            iterated = iterated + rev_iterated
        else:
            return False
    return True

if __name__ == '__main__':

    start_time = datetime.now()

    for number in range(10001):
        if is_lychrel(number):
            candidates.append(number)

    time = datetime.now() - start_time # To get the time of the calculation

    print('In {} were found {} lychrel candidates'.format(time, len(candidates)))
    print(' '.join(map(str, candidates)), 'are candidates.')
    suml = input('Press ENTER to close ')


On my PC (with Intel Atom 2GHz), I got it with .4 seconds.  Could you offer suggestions on making it run faster?


Question: Different tyre width (front and back)
Answer: Riding with a larger tire in the front provides certain advantages. I do this for two reasons:


Less slipping and sliding in the snow: With a bigger tire in the front you get more friction with the ground. This is important because your front tire is a lot more likley to flip you over then your rear because your rear tire has more weight on it.
Vertical cracks: The reason I keep a larger tire on now that it is warmer is to avoid falling due to vertical cracks and my tire getting stuck in them. Basically if your tire can't fit in the crack you can't get stuck in it and flip over.