Here is how I would generate the terms of the finite continued fraction

 1 + 2
       --
       3 + 4
             --
             5 + 6
                   --
                   7

    cf =: {.@] , {.@] + [: ([: %`+/ 0 ,~ ,/)\ (,. }.)
    2 4 6 cf 1 3 5 7x
 1 5r3 29r19 233r151

The underlying idea is that if  tk  is the linear fractional transformation  ak 
% bk + ] 
then the nth term is  b0 + t1 t2 ... tn 0  .  ("term" is defined below)

--Kip Murray

Sent from my iPad

> On Feb 23, 2014, at 4:17 PM, km <k...@math.uh.edu> wrote:
> 
> The generalized continued fraction
> 
>  b0 + a1
>          ---------
>          b1 + a2
>                  ---------
>                  b2  + a3
>                           --------
>                           b3 + ...
> 
> is the infinite sequence
> 
> b0 , b0 + a1%b1 , b0 + a1%b1 + a2%b2 , b0 + a1%b1 + a2%b2 + a3%b3 , ...
> 
> where between the commas I am assuming J's right-to-left evaluation.  The nth 
> term would be
> 
> b0 + a1%b1 + a2%b2 + a3%b3 + ... + an%bn  (still using right to left 
> evaluation).
> 
> What is a good way to calculate this nth term in J?
> 
> 
> For a half-page introduction to generalized continued fractions see
> 
> http://people.math.sfu.ca/~cbm/aands/page_19.htm
> 
> Continued fractions for ln(1+z) and ln((1+z)%(1-z)) are given here
> 
> http://people.math.sfu.ca/~cbm/aands/page_68.htm
> 
> 
> --Kip Murray
> 
> Sent from my iPad
> 
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