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.