Represent recurrent digit in numbers I have try google and this website search engine, didnt find anything.

Let's say that I have a number like this : 111118883458888.

Is there a way to express this number like this (reg exp) : ('1'^5)
 ('8'^3) '345' ('8'^4), but in a mathematical way?

Basically, is there a way to represent recurent digit in numbers?

EDIT -

I'll add why I'm asking the question, basically I wanted a way to represent binary number (like 256 and 512 bits) and you don't feel sick reading them. Thanks for the answers!
Usually, to represent number $\underbrace{111\ldots 11}_k$, I use this expression:
$$
\dfrac{10^k-1}{9}=\underbrace{111\ldots 11}_k.\tag{1}
$$

This way, number $11111888$ could be written as
$$
\dfrac{1}{9}(10^5-1) 10^3 + \dfrac{8}{9}(10^3-1);
$$

and given number $111118883458888$ could be written as
$$
\dfrac{1}{9}(10^5-1)10^{10} + \dfrac{8}{9}(10^3-1)10^7 + 3\cdot 10^6+4\cdot10^5+5\cdot 10^4 + \dfrac{8}{9}(10^4-1)\tag{2}
$$
or this ("compressed") way:
$$
\dfrac{1}{9}(10^5-1)10^{10} + \dfrac{8}{9}(10^3-1)10^7 + 345\cdot 10^4 + \dfrac{8}{9}(10^4-1).\tag{2'}
$$

And here is Wolfram Alpha checking link.
An overbar can be used to denote infinite repetition of decimals, say

$$\frac17=0.\overline{142857}$$

and I don't think there is a strong need to denote the finite repetition of digits.

What about indexed overlines (also for groups) ?

$$\overline{1}_5\overline{821}_3345\overline{8}_4$$

and also recursive ?

$$\overline{1}_5\overline{\overline{821}_3345\overline{8}_4}_5$$