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Tri Tiling

Time Limit : 2000/1000ms (Java/Other)   Memory Limit : 65536/32768K (Java/Other)
Total Submission(s) : 9   Accepted Submission(s) : 3
Problem Description
In how many ways can you tile a 3xn rectangle with 2x1 dominoes? Here is a sample tiling of a 3x12 rectangle.


 

Input
Input consists of several test cases followed by a line containing -1. Each test case is a line containing an integer 0 ≤ n ≤ 30.
 

Output
For each test case, output one integer number giving the number of possible tilings.
 

Sample Input
2 8 12 -1
 

Sample Output
3 153 2131
 

Source
University of Waterloo Local Contest 2005.09.24
 

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