A student writes a computer program that generates a sequence of numbers a1, a2, a3, ... such that a1=a2=1 and ak=a(k-1)*4+1 for 2<k<n. If n=15, find a5.	Pick
A) 85
B) 87
C) 89
D) 93
E) 95
a1=1   a2=1   a3=1*4+1= 
<gadget id="calculator">1*4+1</gadget>
<output>5</output>
5   a4=5*4+1= 
<gadget id="calculator">5*4+1</gadget>
<output>21</output>
21   a5=21*4+1=84+1= 
<gadget id="calculator">84+1</gadget>
<output>85</output>
85   85
<result>A</result>
A student writes a computer program that generates a sequence of numbers a1, a2, a3, ... such that a1=a2=1 and ak=a(k-1)*4+1 for 2<k<n. If n=15, find a5.