# Proof that every natural number is the sum of 9 cubes of natural numbers

What types of proof are there of this result and where can I read about it?

I think that the Hardy-Littlewood circle method can prove that every number is the sum of something like $100000$ cubes, and you can use tables to prove those "small" numbers are all expressible as sums of cubes.. which gives you warings problem but I was more interested in specific proof about the cubes.

Dickson showed that the only integers requiring nine cubes are $23$ and $239$. Wieferich proved that only $15$ integers require eight cubes: $15, 22, 50, 114, 167, 175, 186, 212, 231, 238, 303, 364, 420, 428,$ and $454$ from mathworld

• It is known that every sufficiently large number is a sum of 7 cubes, and conjectured that 4 cubes will do. – Gerry Myerson Oct 25 '12 at 22:18
• actually I would like to know about cubes of integers too,but I think that problem has less known about it. – sperners lemma Oct 25 '12 at 22:23
• 239 needs 9 cubes – i. m. soloveichik Oct 26 '12 at 0:40