MathDB

Define

f(x, y)

to be

\frac{|x|}{|y|}

if that value is a positive integer,

\frac{|y|}{|x|}

if that value is a positive integer, and zero otherwise. We say that a sequence of integers

\ell_1

through

\ell_n

is good if

f(\ell_i, \ell_{i+1})

is nonzero for all

i

where

1 \le i \le n - 1

, and the score of the sequence is

\sum^{n-1}_{i=1} f(\ell_i, \ell_{i+1})

Problem Statement