Integer polygons of given perimeter

Abstract

A classical result of Honsberger states that the number of incongruent triangles with integer sides and perimeter $n$ is the nearest integer to $\frac{n^2}{48}$ ($n$ even) or $\frac{(n+3)^2}{48}$ ($n$ odd). We solve the analogous problem for $m$-gons (for arbitrary but fixed $m\geq3$), and for polygons (with arbitrary number of sides). We also show that the solution to the latter is asymptotic to $\frac{2^{n-1}}n$, and the former (for fixed $m$) to $\frac{2^{m-1}-m}{2^mm!}n^{m-1}$.