What percentage of all positive integers can be written in the form a^b*b^a (where a and b are positive integers)?

Question

A*A + B*B + C*C = D*D + E*E

Answer 1

If one of a or b is equal to 1 then every positive integer can be written in given format. Example: a=1, b=n => a^b*b^a=1^n*n^1=n
So the answer is 100%