The sequence a1, a2, a3, ... , an, ... is such that an=an−1+an−2/2 for all n≥3n≥3. If a3=4 and a5=20, what is the value of a6 ?	Select the correct option:
A) 12 B) 16 C) 20 D) 24 E) 28
Since given that an=an−1+an−2/2, then:   a5=a4+a3/2 --&gt; 20=a4+4/2 --&gt; a4=36   a6=a5+a4/2 --&gt; a6=20+36/2 --&gt; a5=28   Answer: 28.
<result>E</result>
The sequence a1, a2, a3, ... , an, ... is such that an=an−1+an−2/2 for all n≥3n≥3. If a3=4 and a5=20, what is the value of a6 ?