解 考察 n^2+(n+1)^2-(n+2)^2-(n+3)^2=-8n-12所以 原式=-120-8（1+5+9+……+37）=-120-8（1+37）*10/2=-1640
n^2+(n+1)^2-(n+2)^2-(n+3)^2=-8n-12
