2*3*4*5*25*31*41*61
=122*123*124*125
=122*125*123*124
=(123-1)*(123+2)*123*(123+1)
=(123^2+121)*(123^2+123)
=(123^2+122-1)*(123^2+122+1)
=(123^2+122)^2-1
所以:(123^2+122)^2-2*3*4*5*25*31*41*61=1.
2*3*4*5*25*31*41*61
=122*123*124*125
=122*125*123*124
=(123-1)*(123+2)*123*(123+1)
=(123^2+121)*(123^2+123)
=(123^2+122-1)*(123^2+122+1)
=(123^2+122)^2-1
所以:(123^2+122)^2-2*3*4*5*25*31*41*61=1.