In the section Searching of this page of edx, in the last part where students recommended to check their programs by looking for number 2008, is a bug - there is no number 2008 among the numbers generated by
./generate 1000 50. It is easy to check if running
./generate 1000 50 > text.txt and then open
text.txt in gedit and search for number 2008.
On the pset3 page of the cs50 itself there is another number proposed for searching. And that one works.