Combinatorial number system
= Combinatorial number system
{wiki}
Every positive integer $m$ has a unique greedy representation
$$
m=\binom{a_r}{r}+\binom{a_{r-1}}{r-1}+\cdots+\binom{a_s}{s},
\qquad a_r>a_{r-1}>\cdots>a_s\geq s.
$$
This is also called the binomial representation of $m$ at level $r$.
= Binomial representation
{synonym}