Question: What do I write in the conclusion (last statement) of a proof by mathematical induction? (first year of college level)

Something including n=1, p(k), p(k+1) and P(n) i think... but I am not sure how the structure of the sentence should be.(Headbang) I need help on this!

Also, do I have to mention that it is proved by "the principle of mathematical induction"?