I don't remember the derivation off the top of my head, but I suspect the article is referring to the derivation of the formula: > S(1..n) = (n^2 + n) / 2 Thi

I don't remember the derivation off the top of my head, but I suspect the article is referring to the derivation of the formula: > S(1..n) = (n^2 + n) / 2 This was, if I recall, the very first example of inductive proofs we did at my university.