Numbers and words

[simont]

This morning I tried to return a phone call. I managed to dial the wrong number three times at widely separated intervals, and (I later worked out) on all three occasions I transposed the same pair of adjacent digits. And despite carefully cross-checking between the number shown on the display of my phone, the number on the email (my employer's

Comments

[feanelwa]

I have done that for ages. Especially when they are both even and have multiple similar properties! I cope with this by writing the number on a piece of paper with the digits separated into groups. E.g. I will do this to the Anglian Windows phone number since it's a public post and I vaguely associate double glazing with cold calling though they don't necessarily do it:
0800 because it's free, 9 ach nein, 541 5=4+1 203 twins - oh wait - triplets

If I didn't do this I would never phone a right number again except that my phone remembers them for me!

[tigerfort]

Is Si-mo related to El-mo? Si-mo like numbers, but get confused sometimes. El-mo also like numbers, but get confused lots. Si-mo not furry, but that OK, because El-mo not prejudiced.

Separately, the thing that really puzzles me is the way that after a couple of years of regular typing, I started writing typos by hand. Looking down at a page of notes and realising that you've written both "teh" and "adn" out in longhand leaves you (well, me, at any rate) wondering precisely which parts of my brain are now being controlled by skynetchanged in ways I might not expect.

[gerald_duck]

Drat. Now you've got me wondering something not entirely related.

My first thought was that maybe your subconscious was rearranging digits to make the number prime - which would be a feat of Ramanujan proportions. Though clearly both the real number and your transposition ending in 5 militated against this possibility.

But now I'm pondering collections of digits that form a prime number however they are arranged. For example, (1,1,3) where 113 131 and 311 are all prime. It feels displeasing to have repeated digits in the collection, but with that constraint it soon becomes clear no examples of more than two digits exist in base ten. Without the constraint, repunit primes like (1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1) become especially degenerate examples

[simont]

I note that the Wikipedia page you cite links to a page describing just those things. It appears to be quite hard to think of natural questions in recreational maths that haven't been investigated yet :-)

[gerald_duck]

Humph!

In my defence, the Wikipedia article on prime numbers does not link to that page. Guess where I went looking. )-8

At least my conclusions seem to have been correct. And, especially, at least I didn't waste time looking for any more base-ten permutable primes after I'd found the three-digit ones.

That Wikipedia article doesn't touch on gerald_duck's hopefully-far-from-last theorem, though.

[simont]

It's a bit mean to do this, but yes you did ;-)

[arundelo]

"[Time] is a hell of a drug."

[hairyears]

As someone who works at the soft end of software, I have an interest in this kind of thing: I am fairly sure that there are number combinations which are consistently mistyped, and I should probably go looking for published research.

[feanelwa]

the soft end of software
The end you don't wear.

[hairyears]

No, it's soft because it's all a bit GUI.