factor pairs for 240, factor pairs for 243, factor pairs for 20, factor pairs for 40, factor pairs for 25, factor pairs for 28, factor pairs for 27, factor pairs for 45, factor pairs for 49, factor pairs for 26, factor pairs for 48, factor pairs for 42, factor pairs for 14, factor pairs for 21
factor pairs for 240. There are any references about factor pairs for 240 in here. you can look below.