I am supposed to prove a conjecture by induction. I have worked out that the series can be described by:(adsbygoogle = window.adsbygoogle || []).push({});

a = 2,6,12,20,30

S = 2+8+20+40....

(n^2) + n = (1/3) ((n^3)+3(n^2)+2n)

However, i cannot prove it by induction. It seems like there is smth wrong with the K^3.

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# Proof by induction

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