Hello, Dogod11!

I'm not familiar with Time Series.

I've had to come up with my own theories.

An example of time series would be:

Then they say, this series can also be expressed as:

. .

How do they do it and why they develop the series?

It only makes sense if . . . the initial quantity is zero.

Then we have:

. .

And we see the pattern:

. .

which can be written: .

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

did they derive this formula?Why

So we can find, say, the 20th term

. .withoutcranking out the first 19 terms.