If a sequence is defined by an = a(n-1)*a(n-2) + 1 for n>=3

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Magoosh GMAT Instructor

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If a sequence is defined by an = a(n-1)*a(n-2) + 1 for n>=3 [#permalink]

31 Jan 2013, 11:05

00:00

Question Stats:

66% (01:47) correct

33% (00:48) wrong

based on 5 sessions

Attachment:

AA sequence question.JPG [ 18.93 KiB | Viewed 524 times ]

(A) 1
(B) 7
(C) 22
(D) 155
(E) 721

For help with sequence questions on the GMAT, as well as a complete solution to this question, see this post:
http://magoosh.com/gmat/2012/sequences- ... ment-13543

Experts --- feel free to share any tips you would like about sequences, especially recursive sequence such as this one.

Mike :-)

[Reveal] Spoiler: OA

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Kudos [?]: 246 [0], given: 238

Re: recursive sequence [#permalink]

01 Feb 2013, 04:37

I'm not an expert, but, in my opinion GMAT doesn't go too far with recursive sequences.
most of the questions I've seen are like this one - substituting numbers into a term repeatedly till you get the answer. Therefore, the most important things on these questions are not getting bogged down by the length of calculations and not making a stupid calculation error. ( I wrote things way neater than usual on my scratch pad when I had to do recursive calculations

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Re: recursive sequence [#permalink] 01 Feb 2013, 04:37

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	The sequence is defined as follows: A(n) = n/(n+1).	raptr	8	01 Aug 2007, 08:25
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If a sequence is defined by an = a(n-1)*a(n-2) + 1 for n>=3

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If a sequence is defined by an = a(n-1)*a(n-2) + 1 for n>=3

If a sequence is defined by an = a(n-1)*a(n-2) + 1 for n>=3

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