<div dir="ltr">Hello Sergej,<div><br></div><div>if you need to know the Nth digit of a number (i.e. 10987654321), assuming that we say that the rightmost digit is the digit 1, (so in my example 1st digit is 1), you can use:</div><div>> x=10987654321</div><div>> div (mod x (10^N)) (10^(N-1))</div><div><br></div><div><div>So, <i>if you don't need a fast program</i> and you want to compute the digit in position 177486336 of 9^(9^9):</div><div>> x=9^(9^9)</div><div>> div (mod x (10^177486336)) (10^177486335)</div><div>(it takes about 1 minute to compute it)</div><div><br></div><div>or in general if you want to know the N-th digit :</div><div><div>> x=9^(9^9)</div><div>> div (mod x (10^N)) (10^(N-1))</div></div></div></div><div id="DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2"><br> <table style="border-top:1px solid #d3d4de">
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<a href="#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2" width="1" height="1"></a></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Il giorno ven 7 giu 2019 alle ore 16:53 Michael Orlitzky <<a href="mailto:michael@orlitzky.com">michael@orlitzky.com</a>> ha scritto:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On 6/7/19 12:06 AM, Sergej KAREL wrote:<br>
> Hello Francesco,<br>
> Im total beginner. I read some books and online pages.<br>
> I do not know, how to apply your rows if Im looking eg. digit on<br>
> position *177486336 *of the number string<br>
> Sorry for asking so straightforward<br>
> Sergej<br>
<br>
This is a math problem. Read the first few chapters of a book on number<br>
theory -- you'll usually find something like this in the exercises.<br>
<br>
For example, exercise 2.30 in the freely-available "Elementary Number<br>
Theory: Primes, Congruences, and Secrets" by William Stein:<br>
<br>
<a href="https://wstein.org/ent/" rel="noreferrer" target="_blank">https://wstein.org/ent/</a><br>
<br>
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