Brand new to RPN, few questions on bits!

[Kyburo]

Thanks for the tips so far, I'm a little over half way through the manual trying to get my head around taking their examples and modifying it for something similar to a question I'd normally have received.

Figured out bits like programming a recurring sequence of say Un+2 = (Un+1)^2 - 9Un

Although to perform this, I've had to program along the following lines, using V to represent Un+1, and U to represent Un:
U=2
V=5

EQN or RPN the above expression [post equals sign (this time it's an expression also right? since I've an equals sign, but its to explain it's a sequence rather than having a value defined on both sides?)]

(EQN) V^2 - 9xU
STO V
x<>y
STO U
x<>y
RTN

U=5
V=7

Not sure if there is a simpler way of copying the results into the various registers (or if that even makes sense for anyone to follow!)

Anywho, I'll finish going through the manual before asking any more questions, and also go through the guide linked by Jeff.

Also cheers Les! I can completely follow your programs logic thanks to the comments, and I'd not actually realised you could use ENTER^ in that way. Until now I've been using the STO feature at the start each time