Dave Dyer <ddyer@real-me.net> wrote:

"Keith F. Lynch" <kfl@KeithLynch.net> wrote:

...

I can't find any numerology in my post.

I'm sure that's not your intent, but just as astronomical observations and the ability to track the position of astronomical bodies was joined with a system of divination to make astrology, the ability to perform arcane searches for mathematical curiosities opens the door for lunatics or charlatans to make non-mathematical use.

I'm not responsible for any use that other might make of my posts. And even if I *were* responsible, I'd be in good mathematical company: "I remember once going to see him [Ramanujan] when he was lying ill at Putney. I had ridden in taxi-cab number 1729, and remarked that the number seemed to be rather a dull one, and that I hoped it was not an unfavourable omen. 'No', he replied, 'it is a very interesting number; it is the smallest number expressible as the sum of two [positive] cubes in two different ways.'" -- Hardy Watch out for those unfavorable omens. Remember that it's bad luck to be susperstitious. (What would have happened if Hardy had ridden a different taxi? Would Ramanujan have found something just as interesting about *its* number? I like to think so.)

It's easy to stray from abstract math into that territory - witness the recent discussion about messages from god in the expansion of PI,

I blame Carl Sagan for that one.

and for that matter, what's the mathematical significance of "2018"?

In about a week, none at all. :-) We're confronted with the number of each year for a whole year, so we might as well have fun exploring that number. If we get bored with it, we'll get a replacement in a year. It's also a fun programming challenge. Or rather lots of programming challenges. For instance how many different numbers can you get by interpolating various mathematical symbols between the digits of the current year? Some years ago I thought about looping, not over numbers, but over operations. I noticed that * + , - . / were consecutive ASCII characters. I used the comma for concatenation (e.g. 4,2 = 42) and . is of course a decimal point. The other four are of course the standard four arithmetic operations. Then I thought about looping over the ways to parenthesize these operations, and "discovered" the Catalan sequence. Real math, real programming. Today I've been thinking about how I would go about determining which is the last Fermat number which does *not* contain 2019 as a substring. I'm convinced that there is one, and that there isn't a last power of two with that property. I've since answered my own question as to which are the first powers of two that *begin* with 2018 and 2019: 4665 and 2044 respectively. Proving that there must be powers of two (or of any other positive integer except one or a power of ten) that begin with any desired integer is serious math. Someone who doesn't know that might be tempted to ascribe mystical significance to the fact that a number that's meaningful to them has that property.