GWD19-9

[mcpopcorn2001]

Q9:
A certain computer program generates a sequence of numbers a1, a2, … , a n such that a1 = a2 = 1 and ak = ak-1 + 2ak-2 for all integers k such that 3 ≤ k ≤ n. If n > 6, then a7 = ?

A. 32
B. 43
C. 64
D. 100
E. 128

ans: B

不會算ㄝ麻煩幫忙一下
謝

[FIG]

好像也是題目不清楚
原式應該是這樣 ak = a(k-1) + 2(a(k-2))
帶一下43就出來了

[mcpopcorn2001]

啊~
原來是題目的問題啊
謝謝喔