Tau Zero

This was not the book I thought it was.
Long ago I read a book about a group of people were traveling in space and for some reason they are able to solve very complex problems.
In particular, they developed a way to send a lot of text by converting it to a single very large number.
This book involves a group of people traveling through space at very high velocities and enormous relativistic effects occur.
It's very interesting but not the one I thought.