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Re: Code required for recurrence relations

• To: mathgroup at smc.vnet.net
• Subject: [mg90285] Re: [mg90235] Code required for recurrence relations
• From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
• Date: Fri, 4 Jul 2008 03:59:39 -0400 (EDT)
• References: <200807031010.GAA03077@smc.vnet.net>

On 3 Jul 2008, at 19:10, Ant King wrote:

> Hi all
>
> I am running v. 6.03 and would like to know if anyone is aware of  
> any code
> (or has a function) that will perform the following task
>
> Take a generating function, such as 2*x/(1-x)^2, and use it to  
> extract the
> recurrence relation from whence it came - in this case it just  
> generates the
> even numbers
>
> So the function will be something like f[2*x/(1-x)^2,u,n] and would  
> output
> something like u[n]->u[n-1]+2
>
> Many thanks


Your f is (essentially) SeriesCoefficient:

SeriesCoefficient[2*(x/(1 - x)^2), {x, 0, n}]
  2*n

Andrzej Kozlowski
>
>
> Ant
>

• References:
  • Code required for recurrence relations
    • From: "Ant King" <mathstutoring@ntlworld.com>