# Notation to describe vector

I want to describe a vector of n length, where each element is described by it's index. What is the correct notation?

As it is now, to describe the vector [ 1 4 9 16 ] i write:

$\{a^{2}\}_{a=1}^{4}$

But I can't remember if this is something i made up in my own mind.

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I think you mean [1 4 9 16]... –  Jesse Madnick Apr 14 '11 at 8:19
Using $\{ \ldots \}$ would suggest a set. You should use $( \ldots )$ instead. –  Zhen Lin Apr 14 '11 at 9:13

I will advise you to write $\mathbf{a} = (a_1,...,a_4 )$ where $a_i = i^2$. A little bit longer but correct.