Staples

I like to keep our grocery deliveries down to one-a-month which makes it difficult if ever they are out of something (or my personal shopper can't find it). One obvious remedy is to hoard more than a month's worth of staples so that out-of-stock items don't impact the unchanging (and somewhat inflexible) daily menu. Of course one can't really do that with milk and yogurt. Last summer I compensated by walking over to the nearby FreshCo for replacements. With the recent uptick in snow and Omicron, I perceived such a venture as too challenging. So last month I tried a second order, but from a different grocery delivery service. Even that was not able to procure me those big boxes of Bran Buds, so I resorted to asking Amazon for five of them (back on January 27). It was never going to be a fast delivery because (I think) they had to wait on Kellogg's but I still had a couple of big boxes and a couple of small ones on hand, so no problem. Then the Ambassador Bridge blockade made me worry a bit about it. The order arrived today! In the above photograph they are on the second shelf from the top.

Number fourteen

This is a screen grab of today's probable-prime top-discoverers leaderboard that updates the one I posted on 7 May 2021. My production score now places me at #14. I am unlikely any time soon (if ever) to reach #13 and there is ample opportunity to be displaced downward by other people's efforts.* Of the 1584 PRPs noted, 1532 are Leyland primes. I reached my 1500th Leyland prime on 9 September 2021.

My worksheet (above) shows, at the bottom, the 74 cores currently working on Leyland interval L(302999,10) to L(303999,10) in which I have found so far 11 Leyland primes. It should be done in early March. After this I will do interval L(303999,10) to L(304999,10), taking me into May. This will then complete my attempt to find all Leyland primes in the interval L(299999,10) to L(304999,10). My thinking for what comes next has changed somewhat since the recent finds by the Levai brothers of five Leyland primes larger than 500000 decimal digits (at the bottom, here). I may to try to find a Leyland prime with one million (or more) decimal digits.

* Update (28 February 2022): Only one week later and I am again at #15 as Anonymous moved from #18 to #9.

80 on 80

An 80-year-old woman crossing the street died after being struck by an 80-year-old woman driving a Honda. Strikes me as a starting point for a science-fiction story or revenge drama.

2022, for example

As we entered the current calendar year, James Propp (in a math-fun forum) noted a Dan McQuillan tweet on the embedding of the integer 2022 in its base-three representation:

2202220

The property is not the sole domain of 2022, but rather of a sequence of such integers wherein 2022 is the sixteenth term. James wanted to find out if this sequence was infinite. His argument had it that for length-d integers there should be slightly more than d solutions. Actual number of solutions for d up to 26 are:

3, 3, 6, 4, 4, 0, 0, 3, 3, 10, 0, 15, 14, 20, 8, 13, 20, 25, 9, 21, 14, 20, 23, 17, 8, 18.

That's 281 solutions altogether, thus far. Here are the last 18 (26-digit) solutions:

12011102001112020010002201020010222122111111112022112

12011102001112020010010002110100202102022110210022001
12120120221001100110120020101011000001200201100221210

12120200122001222012202121222002101201220202020112112

12121211002200121012200100101222020222010202110221012

12121211010102002200002122022001122122022111002211220

12121211102211101101221101122010121002020112121202201

12121211110112212210222021122222211212101012002120022

12121211202222011121002000222100101122011102212211110

12121211210200212010210010102210210002222221002210221

12121221220001002121001110110111221111010011221120222

12121222012222220211020021122201211121212110012112122

12121222020000010000010220110120001111001100122121202

12200002021122110111202210110110201200122021112110022

100202112102120012102220200111102002122102011100001122

100202112102120102102210221000121021121102121111011222

100211210200212022120220202012210222011001201111010120

100211210200212022120221010210222021011222010102002111

[last updated 28 March 2022]

A coincidence of dates

Every few years I manage to discover something previously unknown in my genealogical meandering. Recently it was the children of Wilhelmine Elisabeth Havermann Rademacher on an Ancestry website. Note that the site incorrectly positions her among the children. Elisabeth (known as Sette) was a sister of my grandfather Friedrich (known as Fritz) Havermann (1869-1945).

Sette's children are welcome additions to my personal "Havermann" family tree. There was another piece of information on that Ancestry website: Elisabeth's death date is given as 17.05.1943, supposedly in Arnsberg. A search for that specific date yields a number of hits related to Operation Chastise, wherein the dam at the Möhne reservoir was destroyed. Many of the deaths from the resulting flood occurred in Neheim (which, since 1975, is a part of Arnsberg). Neheim is not only where I was born, but also (I believe) the hometown of my grandaunt Elisabeth Rademacher. If Sette was a casualty of that flooding, this was not something of which I had been previously aware. Mind, prior to my father's death, his aunts and uncles (and their offspring) generally were not something of which I recall being really conscious. If he had ever talked about any of them, it failed to make a sufficient impression on me (i.e., that they were his relatives).

My research associate, Marlene Frost, has Ancestry access and was able to dig up the 1928 and 1936/37 address directories for Neheim showing that Elizabeth and some of her children lived at Möhnestraße 11, not far from the Möhne river (downstream from the reservoir). The Möhne joins the Ruhr in Neheim. Sette's death informant, instead of providing particulars, had simply made a reference to the Möhnekatastrophe, hence the date.

Möhnetalsperre 17 May 1943 (Fotarchiv Ruhrverband)

How not to communicate one's GPS location

Alas, Apple has made the ad unavailable. "The owner of this Apple Watch has taken a hard fall and is not responding to their watch. The emergency location is latitude 47.7, longitude -117.5, with an estimated search radius of forty-one metres."

Bob B. (presumably no relation to the unfortunate Amanda A. [video ad also now unavailable] who flipped her car in fast-rising, muddy water) was knocked unconscious mountain biking in a forest just west of Spokane WA with his watch supposedly making the 911 call. No doubt countless targets of the advertisement will ask Google Maps for the location of the coordinates:

Wow! Exactly on a bicycle-friendly road in a wooded area. But there is something amiss. To achieve such pin-point accuracy one needs precision somewhat beyond the given tenths of a degree latitude/longitude. 47.7000 N, 117.5000 W would do it, although the 41-metre search radius suggests 47.700 N, 117.500 W is probably sufficient. A GPS location is likely given in degrees/minutes/seconds (not decimal degrees) and this would have the desired accuracy. I am not acquainted with the Apple Watch emergency-call GPS specifics but I will point out that by approximating the location as 47.7 N, 117.5 W (dropping the terminal zeros), it implies an error box of ~7.5 km east-west and ~11.1 km north-south. That's a search-area of over 8300 hectares! Poor Bob.

47.7º N, 117.5º W, approximation error box (in magenta), click to enlarge

Telephone puzzler

Local calls appeared to be getting through on our home-phone landline but not long-distance calls, as evidenced by a handful of instances over the course of a month. I was certain that the problem lay in some distant Bell relay device and that the technician likely wouldn't have to come into the house. I was wrong.

Ekene, technician, connecting a new cable to a nearby Bell hub

Snow

Early this morning, coming home after the dog-walk. Twelve hours later we had ~40 cm.

10*9*8+7+6+5+4*321

Happy New Year!

The adventure begins (fingers crossed)

photo/ornament courtesy ScienceSocks