[seqfan] Re: Interesting discovery by Dan Preston concerning a Recaman-like sequence

[Hans Havermann]

I'm running the code (with 11281) as I write, so far without interruption. The printouts of how many iterations have been reached are now > 1.75*10^12. The only issue I have is that the file that is keeping track of the bit vectors is showing at first glance to be > 5.3 TB, which is impossible because the storage drive is only 2 TB and a system check appears to indicate that it still has 1.25 TB of space available.

> On Mar 20, 2019, at 12:10 PM, hv at crypt.org wrote:
> 
> I've written some code to attempt this, available via commit b8eef3ea at
> <https://github.com/hvds/seq>.
> 
> This keeps a bit vector of the values seen, split into chunks, and spills
> chunks to disk to limit the memory use.
> 
> It appears to give correct values for known n, but trying it with 11281 it
> gives a bus fault a little after 12,213,813,248 (which takes about 5 minutes).
> That's around the time I run out of disk space, so that may be the whole
> of the problem, but there may be a deeper problem.