There is a sequence ni such, in which i is a positive integer, ni+1=2ni.
If n1=1, n2=2, n3=4, n4=8, what is the scope including n31? Choose the correct choice from the following answers.
A) 100~1,000 B) 1,000~10,000 C) 10,000~100,000 D) 100,000~1,000,000 E) 1,000,000,000~
-&gt; ni=2^(i-1) -&gt; 2^10=1,024&gt;1,000=10^3 -&gt; n31=2^30=(2^10)^3&gt;(10^3)^3=10^9   Thus, the answer is 1,000,000,000~.
<result>E</result>
There is a sequence ni such, in which i is a positive integer, ni+1=2ni.
If n1=1, n2=2, n3=4, n4=8, what is the scope including n31?