MathNet 1988 — Part 01 Question 31

Show that there are infinitely many odd composite numbers in the sequence $1^{1}$, $1^{1} + 2^{2}$, $1^{1} + 2^{2} + 3^{3}$, $1^{1} + 2^{2} + 3^{3} + 4^{4}$, ... .