00:02
So for this question, we have the first tempters that go 0 -1 -1 -2 -3 -3 -4 and 5.
00:08
We know that f -sub 1 is equal to 0, f -sub 2 is equal to 1, f -3 is equal to 2, f -4 is equal to 4, f of 5 is equal to 6, then 9, then 12, then 16, then 20, and then 25.
00:23
Now using a sum formula, you're going to end up with the formula of n squared plus n, divided by two.
00:31
So for the odd terms of this series, including f of 1, you're going to realize that you can use this formula here.
00:39
Therefore, you can write that f of n, f of n, is equal to one -fourth of n squared minus 1 over 4.
00:50
So for even terms of the series, you should be able to gather, so this is for odd terms...