Question 498943: Hello:
I am working on a practice test and it would be dishonest of me to ask you the same question. However, I am having a horrible time discerning how to write a recursive pattern. I know how to find the pattern, no problem, see that right away, but when it comes to figuring out the pattern I get a mental block.
Is there a resource you can recommend to me to sort this out? I would be happy to study it as I want to understand this.
Tina
Answer by chessace(471)   (Show Source):
You can put this solution on YOUR website! There are several books, no doubt some of them online.
It's easy enough to explain:
Once you see the pattern, say it's
1 3 7 15 31 ...
which you see is "double previous then add 1",
The recusive formula is not far off:
x(1)=1
for n>1, x(n)=2*x(n-1)+1
Even sequences that are "too easy" such as the even numbers,
can be expressed recursively:
x(1)=2
n>1: x(n)=x(n-1)+2
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