# What is the preferred symbol to indicate the least positive number to start a sequence?

I need a least positive number and I am considering $\delta$, $\epsilon$ and $\theta$. Which one would be best to start a sequence? Are there any others I should also consider?

Edit:

$a(0)\text{:=}\theta$

$a(n)\text{:=}\left \lceil \left(x=a(n-1)\right)+x^{\frac{1}{2}}\right\rceil$

The starting number can be anything $0<\theta<1$

• To start a sequence of what? – MJD Jul 8 '12 at 21:34
• I think there is no answer to this question, but at minimum you should give a lot more information. What are you doing with this sequence? What is it a sequence of? What does the phrase "the least positive number to start a sequence" mean? – Zev Chonoles Jul 8 '12 at 21:37

$\delta$ and $\epsilon$ have particular common uses which seem not the same as yours, so given those choices I would use $\theta$. But I'd have to know more about your use to say for sure.
A fairly commonly used name for the starting point, at least for arithmetic and geometric sequences, is $a$. Another possibility is $c$, for a generic constant.
Or else in your case, depending on the indexing, you could use $a(0)$, or $a(1)$. Using Greek letters in this type of context is less traditional. But there is nothing wrong in doing so.