Tuesday 2 January 2018

When I was in high school, I was not a diligent student of English. I would try to do the reading on the subway ride, and not very well. One morning, I was on page 38 when I got to my stop. I didn’t have a bookmark, and I didn’t like to turn down the corners of pages, so to remember my place, I thought about what was interesting about the number 38.

Hmm, 38 is twice a prime. It’s one more than 37, which is a prime. Oh, and 39 is three times a prime. Interesting: a sequence of three consecutive numbers that are respectively 1-times, 2-times, and 3-times a prime. BTW, it worked: to this day, I remember what page I was on!

Then a recent tweet brought back this interesting confluence: 2018 has the same property. 2017 is a prime, 2018 is twice a prime, and 2019 is three times a prime.

It turns out this property is rare. There are only eleven numbers less than 3000 like this: 14, 38, 158, 542, 878, 1202, 1382, 1622, 2018, 2558, 2858; and only 541 such numbers less than 1,000,000.

So 2018 is a truly unusual year. 2017 was difficult politically, but there are hopeful signs of a turning tide. Here’s to the year ahead, and fighting the good fights: personally, locally, and nationally.

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