
Another Infinite Game
Problem 986
Peter is playing another game on an infinite row of squares, each square of which can hold an unlimited number of tokens.
Initially, every square contains a token.
Given positive integers $c$ and $d$, each move of the game consists of the following steps:
- Choose two tokens $X$ and $Y$ such that $Y$ is $c$ squares to the right of $X$.
- Move both $X$ and $Y$ to the square that is $d$ squares to the right of $Y$.
Peter's goal is to move as many tokens as possible into one square. For example, with $c = 2$ and $d = 1$, it is possible to move $7$ tokens into one square, following these steps (where red color marks the chosen tokens):
... 1 1 1 1 1 1 1 1 ...
... 1 1 1 1 0 1 0 3 ...
... 1 1 1 0 0 0 2 3 ...
... 0 1 0 2 0 0 2 3 ...
... 0 0 0 1 2 0 2 3 ...
... 0 0 0 1 1 0 1 5 ...
... 0 0 0 1 0 0 0 7 ...
However, it is not possible to move $8$ tokens into one square.
Let $G(c, d)$ be the maximum number of tokens Peter can move into one square. For example, $G(2, 1) = 7$. You are also given that $G(1, 2) = 7$, $G(3, 1) = 11$, $G(2, 2) = 3$ and $G(1, 3) = 15$.
Find the sum of $G(c, d)$ for all pairs of $c, d$ with $1 \leq c, d \leq 160$.