Let n be a positive integer. Then the number of common factors of n2 + 3n + 1 and n2 + 4n + 3 is
1
Two positive integers p and q will have a common factor other than one, only when is a divisor of both p and q. Now, (n2 + 4n + 3) - (n2 + 3n + 1) = n + 2 and it is a not a factor of n2 + 4n + 3 = ( n + 1 ) (n + 3 ) or n2 + 3n + 1 = ( n + 1 )2 + n. Hence the common factor of n2 + 4n + 3 and n2 + 3n + 1 is just 1.