#!/usr/bin/python3 # mari wahl @2014 # marina.w4hl at gmail # ''' The Fibonacci sequence is defined by the recurrence relation: Fn = Fn−1 + Fn−2, where F1 = 1 and F2 = 1. Hence the first 12 terms will be: F1 = 1 F2 = 1 F3 = 2 F4 = 3 F5 = 5 F6 = 8 F7 = 13 F8 = 21 F9 = 34 F10 = 55 F11 = 89 F12 = 144 The 12th term, F12, is the first term to contain three digits. What is the first term in the Fibonacci sequence to contain 1000 digits? Answer: 4782 ''' def fib(num=1, num_before=1): found = False num_before, num = num, num + num_before if count_digits(num) == 1000: found = True return num, num_before, found def count_digits(num): num_str = str(num) return len(num_str) def main(): found = False num = 1 num_before = 1 count = 2 while not found: num, num_before, found = fib(num, num_before) count +=1 print(count) print('Done!') if __name__ == '__main__': main()