11^3+12^3+13^3+14^3+15^3
=(1^3+2^3+……+15^3)-(1^3+2^3+……+10^3)
=(1+2+3+……+15)^2-(1+2+……+10)^2
=[(1+15)*15/2]^2-[(1+10)*10/2]^2
=120^2-55^2
=(120+55)(120-55)
=175*65
=11375是因式分解，不是计算结果(1+2+3+……+15)^2-(1+2+……+10)^2

=[(1+2+3+……+15)+(1+2+……+10)][(1+2+3+……+15)-(1+2+……+10)]
=[2(1+2+3+……+10)+11+12+13+14+15](11+12+13+14+15)