Question

先阅读下列材料、再解答后面的问题、

Answer 1

n（n+1）（n+2）（n+3）+1=n(n+3)(n+1)(n+2)+1=(n^2+3n)(n^2+3n+2)+1

=(n^2+3n)^2+2(n^2+3n)+1=(n^2+3n+1)^2

n^2+3n+1为整数,命题得证