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A weird recurrence relation
Problem 463
Published on 15 March 2014 at 10:00 pm [Server Time]
The function $f$ is defined for all positive integers as follows:
- $f(1)=1$
- $f(3)=3$
- $f(2n)=f(n)$
- $f(4n + 1)=2f(2n + 1) - f(n)$
- $f(4n + 3)=3f(2n + 1) - 2f(n)$
The function $S(n)$ is defined as $\sum_{i=1}^{n}f(i)$.
$S(8)=22$ and $S(100)=3604$.
Find $S(3^{37})$. Give the last 9 digits of your answer.
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