数列求和:1*3+3*5+5*7+.+(2n-1)(2n+1)

问题描述:

数列求和:1*3+3*5+5*7+.+(2n-1)(2n+1)

1*3+3*5+5*7+.+(2n-1)(2n+1)
=(4*1^2-1)+(4*2^2-1)+...+(4n^2-1)
=4*(1^2+2^2+...+n^2)-n
=4*n(n+1)(2n+1)/6 - n
=.