Write a recursive formula for the sequence 15, 26, 48, 92, 180, ... Then find the next term.

A) an= 2an – 1 – 4, where a1 = 15; 356
B) an= 2an – 4, where a1 = 15; 356
C) an= 4 + 11 · 2n–1, where a1 = 15; 356
D) an= 3an – 1 – 19, where a1 = 15; 356

Question

Write a recursive formula for the sequence 15, 26, 48, 92, 180, ... Then find the next term. 

A) an= 2an – 1 – 4, where a1 = 15; 356 
B) an= 2an – 4, where a1 = 15; 356 
C) an= 4 + 11 · 2n–1, where a1 = 15; 356 
D) an= 3an – 1 – 19, where a1 = 15; 356

.sam. · Answer

Well what's your choice?

immings · Answer

I didn't see your reply until just now. So the answer (from before) is B and it is recursive because you can use this to find the sequence until infinity.

anonymous · Answer

I learned that $$a_n = a_n - 1 + d$$ is the recursive formula 
so shouldn't it be
$$ a_n = 2[a_{n-1}] - 4 $$