MathCastle
Proof WritingSuperchallengeDirect Proof

Direct Proof · Superchallenge problem

For how many integers nn with 1≤n≤10001 \le n \le 1000 is gcd⁡(n2+1, (n+1)2+1)>1\gcd\big(n^2 + 1,\ (n + 1)^2 + 1\big) > 1?