Friday, May 19, 2023

Agent orange

This late-evening marauder comes as close to being "orange" (especially in the tail) as one might deem possible. Close inspection suggests that the effect might just be a whitened mixture of "brown". A search finds that the descriptive word for it is "erythrism". This particular raccoon paced our back- and side-yards for a half-hour or so before finally climbing the fence into a neighbour's yard. This included ventures onto the back deck and peering into the kitchen door. When I went out in order to scare it away, it was somewhat unconcerned by my approach — perhaps even attracted to it — as though it was tame. This leads me to suppose that it might be suffering from distemper.

Update: Two days later it was on its way to be euthanized...

Friday, May 12, 2023

A million-digit Leyland prime (ryanp)

Ryan Propper ("ryanp" on Mersenne forum) had not contributed any Leyland primes prior to Wednesday, when he proclaimed this 1433792-digit integer to be a PRP. Then yesterday, he added another (at a mere 582101 digits) that had a small y [L(x,y) defines a Leyland integer as x^y+y^x, x≥y; here y=2]. The current top-five Leyland prime leaderboard now sports three million-digit Leyland primes (the first column is the number of digits):

1433792    (300102,59935)   Ryan Propper   May 2023
1000175    (218767,37314)   Gabor Levai    Mar 2023
1000027    (211185,54364)   Gabor Levai    May 2022
 582101   (1933695,2)       Ryan Propper   May 2023
 506429    (107890,49423)   Miklos Levai   Feb 2022

Tuesday, May 09, 2023

A million-digit Leyland prime (ramp-up)

This is an update to my previous "retry" post, wherein I announced a new million-digit Leyland prime search attempt. Today I finished ramping up the search from the initial 12 processes on 3 computers (covering 20% of the search space) to  57 processes on 18 computers (covering about 70% of the search space). My search last year had the same 18 machines doing 108 processes but I subsequently discovered that this overloading of processes was highly inefficient and detrimental to the effort. My current 57 processes should all be done (roughly) in early November and I can assign the remaining 30% of the search space — process by process, as they come due — at that time.