How to solve the equation?

[ttokoro]

All numbers are natural numbers. (Integer of n>0).

How to solve the equation? Prime 7 can not solve the answers.

The answers are 

 

[Werner_E]

Mathcad never was the tool to solve diophantic equations (apart from an extension pack which worked only in a very early version of MC).
You get a result in MC15 but its in no way helpful:

Maybe Luc can show us what MC11 with Maple can come up with

[-MFra-]

[ttokoro]

n and k are integer and n>0.

[-MFra-]

I got distracted. It is a Diophantine equation.  See on Wikipedia.

[LucMeekes]

Mathcad 11/Maple:

and with

you get only the first answer.

Success!

Luc

[Fred_Kohlhepp]

Well, you can find the answer, but it's not really "solving"  . . .