I’m trying to remove the summation sign from this formula, is this possible?

1+500∑k=1(4(2k+1)2−12k)

**Answer**

Hints: expand 4(2k+1)2−12k and use

n∑k=1k=n(n+1)2

n∑k=1k2=n(n+1)(2n+1)6.

You can find a proof of the second formula in this post of mine (in Portuguese).

**Attribution***Source : Link , Question Author : Timo Willemsen , Answer Author : Américo Tavares*