OEIS A229580 mini challenge (RPL)

[Gerson W. Barbosa]

(05-01-2018 08:56 PM)Gerald H Wrote:  

(05-01-2018 07:40 PM)Gerson W. Barbosa Wrote:  Hello, Valentin,

Thank you very much for you valuable contribution!


Of course not! This should have been opened to other calculators in the first place, my bad. As I said, more important than the resulting optimization was the better formula the participants would eventually come up with. My first attempt using your formula gives me 40 bytes on the hp 50g, but others may improve on that.

By factoring the first few elements, I have obtained an = (2n - 1)*2^(2n - 3), which is probably the same formula Joe has come up with, since he used the same method I did. Both formulas are of course equivalent and hopefully will make for even better optimizations on the original target.

Best regards,

Gerson.

Your formula returns

1/2

for input

1

The first element in the sequence is anomalous. The formula is valid for n > 1, but you are right, I’ve forgotten to mention that. Fortunately a simple built-in function, available on the wp34s as well, will turn that fraction into the right integer while keeping all the remaining elements unchanged, as we are aware of.