Yet another Fibonacci mini-challenge (HP-42S/Free42)

[Gerson W. Barbosa]

(12-06-2018 01:46 AM)Thomas Okken Wrote:  

(12-05-2018 04:14 PM)Gerson W. Barbosa Wrote:  14 steps... if you notice that asinh(1/2) = ln(phi) then you can easily do it in ten steps.

I'll admit I don't see it. Replacing 5 SQRT 1 + 2 / with 0.5 ASINH E^X saves three lines, so that leaves 11, not counting the LBL and the END. How do you eliminate another two lines?

EDIT: oh wait, it's easy to eliminate one more line by replacing the E^X X<>Y Y^X with * E^X.
But that's still one line longer than the challenge...

Yes, that’s it! For 9 steps I made a slight change in the formula:

F(n) = CEIL((phi^n - 1)/sqrt(5))

The only problem is my two-step sequence for CEIL won’t work for integer arguments (which will affect F(0) only)