/extra/project-euler/016/016.factor

 1! Copyright (c) 2007, 2008 Aaron Schaefer.
 2! See http://factorcode.org/license.txt for BSD license.
 3USING: math.functions project-euler.common sequences ;
 4IN: project-euler.016
 5
 6! http://projecteuler.net/index.php?section=problems&id=16
 7
 8! DESCRIPTION
 9! -----------
10
11! 2^15 = 32768 and the sum of its digits is 3 + 2 + 7 + 6 + 8 = 26.
12
13! What is the sum of the digits of the number 2^1000?
14
15
16! SOLUTION
17! --------
18
19: euler016 ( -- answer )
20    2 1000 ^ number>digits sum ;
21
22! [ euler016 ] 100 ave-time
23! 0 ms ave run time - 0.67 SD (100 trials)
24
25SOLUTION: euler016