# Problem 463: A weird recurrence relation ![graphic](img463.gif) 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.