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# Recursion

2 replies to this topic

### #1 mmiguel

mmiguel

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Posted 21 October 2012 - 10:43 AM

Find a closed-form expression for F(a,b) where:

F(a,b) = F(a-1,b) + F(a-1,b-1),
F(a,0) = 1 for all a
F(0,b) = 0 for all b

a and b are positive integers
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### #2 Anza Power

Anza Power

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Posted 21 October 2012 - 02:55 PM

What does F(0,0) evaluate to? you need it for F(1,1)

Spoiler for

Edited by Anza Power, 21 October 2012 - 03:04 PM.

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### #3 mmiguel

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Posted 21 October 2012 - 07:53 PM

What does F(0,0) evaluate to? you need it for F(1,1)

Spoiler for

F(0,0) = 1
Sorry for leaving that out.

Nice work, you are correct!
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