1^2+2^3+3^3+...+(2012^2015)^3
=(1+2+3+..+2012^2015)^2=A^2
A=(2012^2015+1).2012^2015/2
=(4^2015.503^2015+1).2^4029.503^2015
=[(...824).(...343)^31+1].(...912).(...343)^31
=[(...824).(...407)+1].(...912).(...407)
=[(...368)+1].(...184)
=(...369).(184)=(...553)
=>A^2=(...553)^2=(...809)
Vậy 3 chữ số tận cùng là 809