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algebra intermediate
Problem
Define a sequence recursively by and be the remainder when is divided by for all Thus the sequence starts What is
Solution
The first few terms are as follows: Since and and each term depends only on the previous two terms, the sequence becomes periodic, with period 8.
Then the sum of the eight consecutive terms is simply the sum of the eight terms in the period, which is
Then the sum of the eight consecutive terms is simply the sum of the eight terms in the period, which is
Final answer
9