# "n", "4n", "+4n", "-4n", "n+1", "4n-1", "+4n-1" (and other variations)
return [0, 0]
unless $equation =~ /^\s*((?:\+|-)?(?:\d+)?)?n\s*((?:\+|-)\s*\d+)?\s*$/i;
- return [$1 eq '-' ? -1 : $1 eq '' ? 1 : $1, join('', split(' ', $2 || 0))];
+ return [$1 eq '-' ? -1 : !length $1 ? 1 : $1, join('', split(' ', $2 || 0))];
}
sub _match {