The sum of g(k) k powers. G(2)=4, which means "the sum of four squares" instead of "the sum of four squares".

The square number is 0, 1, 4, 9, 16. 1=0+0+0+ 1, 2=0+0+ 1+ 1, 3=0+ 1+ 1+ 1。 It seems a bit boring, but it is meaningful to prove that it can be applied to all numbers.

G(k) is a function described by language, not by Fu Wuwei. He didn't mention it here. I don't know what g(4) is, but someone has to prove it.