1
n(n+1)(n+2)(n+3)+1=(n²+3n+1)²
2
n(n+1)(n+2)(n+3)+1
= [n(n+3)] [(n+1)(n+2)]-1
=(n²+3n)(n²+3n+2)+1
=(n²+3n+1)²
1、1*2*3*4 +1=(1*4+1)^2=5^2
2*3*4*5+ 1=(2*5+1)^2=15^2
3*4*5*6+ 1=(3*6+1)^2=19^2
n(n+1)(n+2)(n+3)+1=[n*(n+3)+1]^2=(n^2+3n+1)^2
2、n(n+1)(n+2)(n+3)+1
=(n^2+3n)(n^2+3n+2)+1
=(n^2+3n)^2+2(n^2+3n)+1
=(n^2+3n+1)^2
n(n+1)(n+2)(n+3)+1=[n(n+3)+1]^2
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)[(n^2+3n)+2]+1
=(n^2+3n)^2+2(n^2+3n)+1
=(n^2+3n+1)^2
=[n(n+3)+1]^2