化简（a+1）（a2+1）（a4+1）...(a21000+1)

（a+1）（a2+1）（a4+1）...(a21000+1)
=[(a-1)（a+1）（a2+1）（a4+1）...(a21000+1)]/(a-1)
=[(a^2-1)（a2+1）（a4+1）...(a21000+1)]/(a-1)
=[(a^4-1)（a4+1）...(a21000+1)]/(a-1)
=……
=[a^(2^1001)-1]/(a-1)

(a+1)(a^2+1)(a^4+1)...(a^21000+1)
=(a-1)(a+1)(a^2+1)(a^4+1)...(a^21000+1)/(a-1)
=(a^2-1)(a^2+1)(a^4+1)...(a^21000+1)/(a-1)
=(a^4-1)(aa^4+1)...(a^21000+1)/(a-1)
=(a^21000-1)(a^21000+1)/(a-1)
=(a^21000^2-1)/(a-1)

（a+1）（a2+1）（a4+1）...(a21000+1)(a-1)/(a-1)=
(a2-1)（a2+1）（a4+1）...(a21000+1)/(a-1)=
(a4-1）（a4+1）...(a21000+1)/(a-1)=
..............................=
(a32768-1)(a21000+1)/(a-1)
化不动了

转化到平方差公式上。