  In this paper, we provide a formula for the vector space dimension of the
ring $\mathbb{F}_2[x,y,z]/(x^{d_1}, y^{d_2},z^{d_3}, x+y+z)$ over
$\mathbb{F}_2$ when $d_1,d_2,d_3$ all lie between successive powers of $2$. For
general $d_1,d_2,d_3$, we provide a simple algorithm to calculate the vector
space dimension of $\mathbb{F}_2[x,y,z]/(x^{d_1}, y^{d_2},z^{d_3}, x+y+z)$ by
combining our formula with certain results of Chungsim Han (1992).
