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Team Selection Test

Turkey counting and probability

Problem

Find the number of partitions of into two sets such that none of the sets contains two distinct elements whose sum is a power of .
Solution
The answer is . Let us call a partition of into two sets nice partition for , if none of the sets contains two distinct elements whose sum is a power of . Let be the number of nice partitions for . We observe that removing from a nice partition for gives a nice partition for . Therefore, we can obtain the nice partitions for by adding to the nice partitions for . If for some positive integer , then as and , we must add into the set not containing . Therefore, . If for some positive integer , then since , we can add into any of the sets and hence . As and , we conclude that .
Final answer
1024

Techniques

Recursion, bijectionInduction / smoothingRecurrence relations