Show that any two elements (both greater than one) drawn from the same row of Pascal's triangle have greatest common divisor greater than one. For example, the greatest common divisor of 28 and 70 is 14.
I was stumped, so I looked it up. The proof, which is somewhat elegant, dates back to 1978, which strikes me as fairly recent. But it is certainly something that we as a group can recreate.
Stumped
