Is $\Sigma$ only for formula-dependent sequence?

Question

I found on Microsoft Excel that $\Sigma$ feature sums up the numbers in a column.

Reading about $\Sigma$ on Wikipedia, I understand (may misunderstand) that $\Sigma$ is the symbol for function-based sequence.i.e,values of sequence are generated by function (formula).

But I have non-function-based sequence (i.e., sequence is formula-independent): 1,22,1,44,22,0,144.

So, summing up these numbers is 234.

Can I represent total=234 as $\Sigma$=234 ?

Answer 1

Usually it makes sense to create notations in order to use $\Sigma$. In your example:

Let $a_0 = 1$, $a_1 = 22$, $a_2 = 1$, $a_3 = 44$, $a_4 = 22$, $a_5 = 0$, $a_6 = 0$, $a_7 = 144$. Then:

$$\sum_{k=0}^7 a_k=234$$

In maths it is rare to deal with numbers "coming from nowhere".