2021 JMPSC Accuracy Problems/Problem 15
Revision as of 21:34, 10 July 2021 by Samrocksnature (talk | contribs) (Created page with "==Problem== For all positive integers <math>n,</math> define the function <math>f(n)</math> to output <math>4\underbrace{777 \cdots 7}_{n\ \text{sevens}}5.</math> For example,...")
Problem
For all positive integers 
define the function 
to output 
For example, 
, 
, and 
Find the last three digits of ![\[\frac{f(1)+f(2)+ \cdots + f(100)}{25}.\]](http://latex.artofproblemsolving.com/2/4/4/244944bb29f9d9d942d159a2b7178e3b06f5728a.png)
Solution
asdf
