Talk:Ulam numbers

timings for the N^th Ulam number

Using the (new and current) REXX program, the times

It   (the REXX program)   is an   O(2)   polynomial

    0.0000005168509818 N^2  -  0.0004990440614098 N  +  0.5707466809128310
           
    Rsquared = 0.9999999315551220

(The above, as measured and timed on Paul Kislanko's 10-core PC.       -- Gerard Schildberger (talk) 21:38, 4 December 2020 (UTC)

timing for the 100,000^th Ulam number

The total time for the 100,000^th Ulam number using the original REXX program would've taken a little over three years, and that is on Paul Kislanko's PC.     On my old slow PC,   it would've taken about a decade or thereabouts.     -- Gerard Schildberger (talk) 21:22, 4 December 2020 (UTC)

It certainly demonstrates the importance of using a decent algorithm.

I was quite pleased with my first version but it's been trumped twice now by the Phix and XPL0 algorithms! --PureFox (talk) 21:36, 4 December 2020 (UTC)