# -*- coding: utf-8 -*-
"""
Created on Mon Sep 12 11:31:33 2016

@author: efron
"""
"""
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.
"""

def reverse_add(n):
    asStr = str(n)
    reverse = int(asStr[::-1])
    return n + reverse

def palindrome(n):
    s = str(n)
    return s == s[::-1]

def is_lychrel(n):
    for _ in range(50):
        n = reverse_add(n)
        if palindrome(n):
            return False
    return True

lychrel = tuple(n for n in range(1, 10**4) if is_lychrel(n))
print(lychrel)
print(len(lychrel))
