Ternary universal sums of generalized polygonal numbers

Jangwon Ju, Byeong-Kweon Oh, Bangnam Seo

An integer of the form $p_m(x)=\frac{(m-2)x^2-(m-4)x}{2}(m\ge 3)$, for some integer $x$ is called a generalized polygonal number of order $m$. A ternary sum $Φ_{i,j,k}^{a,b,c}(…