Discussion on: Daily Challenge #55 - Building a Pile of Cubes

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Replies for: I just found that 13 + 23 +...+ n3 = (1/4)n2 * (n+1)2 So you would need to reverse that. m=((1/4)n(n+1))2 sqrt(m)=(1/4)n(n+1) //given positive ...

n = 1/2 (sqrt(1 - 8 sqrt(m)) - 1)

Wolfram alpha to the rescue

So my solution would be:

const cubes = m => {
  let n = (Math.sqrt(1 - 8 * Math.sqrt(m)) - 1)/2;

  return n === Math.floor(n) ? n : 0;
}

That's amazing

But it doesn't work. :( Just tested it after posting.