Mathematicians are interested in which natural numbers k can be expressed as a sum of three cubes. Prior to this year, it had been established that this is possible for all k < 1000 except for the following thirteen values:

33, 42, 114, 165, 390, 579, 627, 633, 732, 795, 906, 921, 975.

Earlier this year a solution for k=33 was found [1], so 42 was the next unknown value.

[1] Brooker, A., "CRACKING THE PROBLEM WITH 33", https://people.maths.bris.ac.uk/~maarb/papers/cubesv1.pdf