Wednesday, June 09, 2021

Big time

Nine months ago, I showcased my then-largest Leyland prime find. Things have changed a bit. Here are, as of today, the top ten known Leyland primes:

386434  (328574,15)      Sergey Batalov       May 2014
300694  (110610,523)     Hans Havermann       Jun 2021
300468   (63722,51915)   Hans Havermann       Jun 2021
300337  (314738,9)       Anatoly Selevich     Feb 2011
300035   (67594,27465)   Hans Havermann       Jun 2021
300000   (70599,17756)   Hans Havermann       Jun 2021
265999  (255426,11)      Sergey Batalov       May 2014
223463  (234178,9)       Anatoly Selevich     Jul 2011
172940  (104608,45)      Norbert Schneider    Jun 2021
149984   (45728,1905)    Hans Havermann       Oct 2020

The first column gives the number of decimal digits. The Leyland number of an (x,y) pair is x^y + y^x. Half of the entries have been found in the last seven days!

Monday, June 07, 2021

Much ado about UFOs (UAP)

I'm increasingly annoyed by the lack of skepticism in the current round of media hype about UFOs (UAP). Randall Munroe (xkcd) and Michael Shermer explain what should be obvious:

Wednesday, June 02, 2021

Kelly Rapids

click on the image for a better look

This is a screen grab of Google maps' depiction of a twisting section of Kelly Rapids that appears to be the de facto border hereabouts between the Canadian province of Quebec and the American state of Maine. Very noticeable is the straight-line segmented border approximation of the waterway, as though it was created on a much lower-resolution map. Also noticeable is a small section of the stream that appears to have taken a different, more-northerly route, thus inadvertently ceding some Canadian land to the Americans!