At the library the other day I requested an old book from off-site storage. When I called for it at the circulation desk, I felt as I would when buying some lurid tabloid at the drugstore checkout counter. The book was Erreurs de Mathématiciens des origenes à nos jours, a tell-all tattle-tale account that promised […]

Potentates and plutocrats get their names plastered all over the landscape, but as far as I know you can’t yet buy the naming rights to a theorem in mathematics. You’ve got to actually do the math.
I’ve just (belatedly) discovered a thoughtful catalog and discussion of some mathematical eponyms. Dave Rusin of Northern Illlinois University has […]

Christopher Joyce of National Public Radio is about to launch a series of reports on the “Industriosphere,” in which I am taking part. As in my book Infrastructure: A Field Guide to the Industrial Landscape, the subject matter is all the manmade bits of the environment we live in. (What is that stuff? What does […]

Driving over the river and through the woods yesterday, I was running low on fuel. My car has two kinds of instruments to tell me that I’ll soon be standing by the side of the road feeling foolish. A conventional gas gauge shows the fraction of a tankful remaining, presumably based on readings from some […]

In an item published here last May I stumbled across the sequence

1 3 5 11 21 43 85 171 341 683 1365 2731 5461 10923 21845 43691
87381 174763 349525 699051

which I dubbed “the oddest numbers” but which Neil J. A. Sloane’s Encyclopedia of Integer Sequences calls the Jacobsthal sequence. I asked: Who is or […]

Whether or not anyone else is reading the stuff I’m posting here, the spammers have discovered me. And I’m afraid that “comment spam” is not as amusing as the e-mail variety. I have therefore installed one of those annoying sentry programs that will ask for the answer to a trivial question before allowing you to […]

Three postings here (1, 2, 3) have discussed what happens when you form all pairwise sums and differences from a finite set of integers. The number of differences almost always exceeds the number of sums—a fact that lends special interest to the occasional exceptional sets, with More Sums Than Differences (MSTD).
A question left up in […]

I want to thank those of my friends who sent me links to Jenn Shreve’s amusing collection of bloggers’ “haven’t posted in awhile” excuses and apologies. What has kept me away all this time is the search for an adequate excuse.
Thanks, too, to those of my friends who didn’t send me the links.