COMBARR -- "Combinations & Arrangements lexfile". Adds COMB and ARR to
BASIC.

Size: 168 bytes.

Quickly finds the number of different groups of R things you can take
from a group of P things (COMBinations) or the number of ways of
rearranging P things taken R at a time (ARRangements function, also
known as permutations). Allows greater ranges than allowed by the
FACTorial definitions of these functions.