If n is the product of the integers from 1 to 20 inclusive, what is the greatest integer k for which 2k2k is a factor of n?	Select.
A) 10	B) 12	C) 15	D) 18	E) 20
There are 10 numbers divisible by 2   There are 5 numbers divisible by 4   There are 2 numbers divisible by 8   There is 1 number divisible by 16.   Hence the total number of 2’s in 20! are 10+5+2+1= 
<gadget id="calculator">10+5+2+1</gadget>
<output>18</output>
18   ANSWER:18
<result>D</result>
If n is the product of the integers from 1 to 20 inclusive, what is the greatest integer k for which 2k2k is a factor of n?