Recursive sequences in CAS on prime.

[wawa]

Hello

I can't figure out how to define a recursive sequence in CAS on the HP prime.
I want to define:
u(1)=3/2
u(2)=5/3
u(n)=2003-6002/u(n-1)+4000/(u(n-1)u(n-2))

Of course, I can define this sequence in the sequence app in HOME mode but it gives wrong answers (the sequence is made for that purpose ) so I want to have exact values in CAS.

I made a CAS program with a FOR loop and it works fine but I'm looking for a more straightforward way to do this.
In XCAS, I can type in

Code:

u(n):={si n==1 alors 3/2; sinon si n==2 alors 5/3; sinon 2003-6002/u(n-1)+4000/(u(n-1)*u(n-2)); fsi; fsi;}

and it works.
I am looking for a similar syntax working on the prime too.

thank you for your help.