Waiting, waiting ( Read more... )

And then there's the quasi-factorial sequence (I have been calling them "factorial sequences", until I decided I needed a term for the single numbers). This is a sequence of consecutive integers whose factors collectively include all the prime numbers up to the highest prime factor of any of the numbers in the sequence. The product of all members ( Read more... )

I side-tracked myself last time. Where I intended to head was in the direction of something I call quasi-factorials, for lack of a better name. If anyone can can come up with something better, I will be grateful. If you are American, or have learned English in its American form, remember that as a kiwi, I pronounce the prefix as "quozzee" rather ( Read more... )

I have a fascination with factorials that matches my fascination with the Fibonacci and Lucas series. The factorial of a real non-negative integer is calculated on the basis that the factorial of 0-conventionally represented as 0!-equals 1, and n!=n((n-1)!).

Thus:
1! = 1
2! = 1 × 2 = 2
3! = 1 × 2 × 3 = 6
4! = 1 × 2 × 3 × 4 = 24
5! = 1 × 2 × 3 × 4 ( Read more... )

Keith's stationwagon ZG1767
Andrew's stationwagon ZD1767
Dette's car BBY208
Vic's wife's car BBR208

Vic thinks I'm scary. I didn't even tell him the factors of the numerals. I was probably wise not to tell him about Rory's phone number.

...I was astonished last night to discover that Rory's landline phone number (minus the 03 South Island prefix) has 11 as its highest prime factor. Specifically, his number = 2^12 * 3 * 5 * 7 * 11

Well, I now have a trial version of AVG as my virus protection. Worried by a notice that came up saying 30 days trial-I remember a trial firewall that ran out of time and did $140 odd in damage as it stopped working. Worse than the cost was the loss of certain non-Windows package fonts when the computer people re-installed Windows-Greek, Hebrew and ( Read more... )

My grandson asked me recently what my favourite number is. I told him 510510.

It's easy to impress little kids.

The most obvious thing about the number is that it is a sequence of three digits, which repeats. This simply means that it is a product of a three digit number and 1001, whose prime factors (this is important) are 7, 11 and 13.

More ( Read more... )