[math-fun] Sum of initial nth powers equal to another nth power?

Famously, 1^2 + 2^2 + 3^2 + ... + 24^2 = 70^2 is the only case where the sum of an initial sequence of squares equals another square (ignoring 1^2 = 1^2). Are there any non-trivial examples of this for powers higher than 2 ? (For non-initial cases, 3^3 + 4^3 + 5^3 = 6^3 is the first example, and this website <https://www.mathpages.com/home/kmath147.htm> gives many other examples for cubes.) But I'm interested in when 1^k + 2^k + ... + n^k is an exact kth power for k > 2 and of course n > 1. —Dan