
ZOJ Problem Set  2421
The Recaman's sequence is defined by a^{0} = 0 ; for m > 0, a^{m} = a^{m1}  m if the rsulting a^{m} is positive and not already in the sequence, otherwise a^{m} = a^{m1} + m. The first few numbers in the Recaman's Sequence is 0, 1, 3, 6, 2, 7, 13, 20, 12, 21, 11, 22, 10, 23, 9... . Given k, your task is to calculate a^{k}. Input The input consists of several test cases. Each line of the input contains an integer k where 0 <= k <= 500000. The last line contains an integer 1, which should not be processed. Output For each k given in the input, print one line containing a^{k} to the output. Sample Input
7 Sample Output
20 Source: Asia 2004, Shanghai (Mainland China), Preliminary 