I want to map the various combinations to an unique index: For a given $n$ and $r$, we would have $\binom{n}{r}$ arrangement for values:$[0,\dots,n)$:Ex: For n = 6, r = 3[012,013,014,015,...,345]So, for any given arrangement [012] the index would 0 as its the very first element.Similarly, the index for arrangement for [015] should be 3. Trying to come up a formula to determine the correct index for a given arrangement.
Computing the index in a structured way
combinatorics;discrete mathematics;combinatory logic