m^15+m^12+m^9+m^6+m^3+1
=m^12(m^3+1)+m^6(m^3+1)+(m^3+1)
=(m^3+1)(m^12+m^6+1)
=(m+1)(m^2-m+1)[(m^12+2m^6+1)-m^6]
==(m+1)(m^2-m+1)(m^6+m^3+1)(m^6-m^3+1)