It is known that the Erdos-Straus conjecture is about writing $4/n$ as three unit fractions. My question is that if it is known that if $a>4$ $$ \frac an=\frac1{x_1}+\frac1{x_2}+\cdots+\frac1{x_k} $$ where $k<a$ or it is a conjecture similar to Erdos-Straus one with the same hardness? For instance is it known $$ \frac 5n=\frac1{x_1}+\frac1{x_2}+\frac1{x_3}+\frac1{x_4}? $$

It is known that the Erdos-Straus conjecture is about writing $4/n$ as three unit fractions. My question is whether it is known that if $a>4$ $$ \frac an=\frac1{x_1}+\frac1{x_2}+\cdots+\frac1{x_k} $$ where $k<a$? Or it is a conjecture similar to Erdos-Straus one with the same hardness? For instance, is it known whether $$ \frac 5n=\frac1{x_1}+\frac1{x_2}+\frac1{x_3}+\frac1{x_4} ? $$