gistfile1.py

#!/usr/bin/env python

def count_ones(n):
    res = 0

    while n > 0:
        if n % 10 == 1:
            res += 1
        n /= 10

    return res

def F(n):
    return sum(map(count_ones, xrange(n+1)))

def find_convergence():
    i = 2
    while i != F(i):
        if i % 1000 == 0:
            print "got to %d" % i
        i += 1
    print "found convergence at %d" % i