Representation of positive integers by the form $x_1\mathrm{.}\mathrm{.}\mathrm{.}{x}_k+x_1+\mathrm{.}\mathrm{.}\mathrm{.}+x_k$

For an arbitrary given $k\ge 3,$ we consider a possibility of representation of a positive number $n$ by the form $x_1…x_k+x_1+…+x_k, 1\leq x_1\leq … \leq x_k.$Wealsostudyaquestiononthesmallestvalueof$k\geq3$ in such a representation.