gistfile1.py

def descending_sub_n_digit_palindromes(n):
    while n >= 0:
        k = (n + 1) // 2
        highest = 10 ** k - 1
        lowest = highest // 10

        for x in range(highest, lowest, -1):
            s_x = str(x)            # "abcde"
            rev = s_x[::-1]         # "edcba"

            # For odd n, skip the doubled center digit:
            if n % 2 == 1:
                rev = rev[1:]       # "dcba"

            yield int(s_x + rev)    # "abcdedcba"
        n -= 1


def find_largest_palindrome(n):
    highest = 10 ** n - 1

    for p in descending_sub_n_digit_palindromes(2 * n):
        if p > highest ** 2:
            continue

        for a in range(highest, int(p ** .5) - 1, -2):
            if p % a == 0:
                return (a, p // a)


def print_largest_palindrome(n):
    a, b = find_largest_palindrome(n)
    print('Largest palindrome found!  {} x {} = {}'.format(a, b, a * b))


n = int(input('How many digits in each factor? '))
print_largest_palindrome(n)