WP 34S mini-challenge

[Didier Lachieze]

Here is my solution:

Code:

01 LBL A
02 x²
03 RCL+ L
04 BASE 02
05 SR 01
06 DECM
07 RTN

There are at least two other variants that fit in the same number of steps and provide the same result while not disturbing the stack either 4 or 8 levels. Apart from X, the only register that is modified is L, but it doesn't hold the initial value of X.