What is the sum of all integer values of n satisfying 1≤n≤100, such that n2−1 is a product of exactly two distinct prime numbers?

2 answers

I did that one yesterday, assuming that the
n2 - 1 meant n^2 - 1

http://www.jiskha.com/display.cgi?id=1364361069
n
is an integer that satisfies .
1

n

100