On Additive Representations of Integers by Binomial Coefficients

Abstract

For a fixed integer $k \ge 0$, consider representations of positive integers as sums of binomial coefficients of the form $\binom{n}{k}$. While exact minimal bounds for the number of required summands are known only in a few low-dimensional cases, general existence results have received less explicit treatment. This paper provides: $\bullet$ explicit elementary proofs for the cases ($k=2$) and ($k=3$), $\bullet$ a comparison with classical polygonal number theory, $\bullet$ an explanation of why naive counting arguments fail for general ($k$), $\bullet$ conditional and unconditional existence results for general ($k$), $\bullet$ and a discussion of quantitative bounds and computational evidence. Together these give a unified and transparent framework for understanding additive representations by binomial coefficients.