[r-t] irregular leadheads

[freepabs at freeuk.com]

> There are 24 (4!) possible leadheads but I shall avoid things like 
3254 =
> (2 lead course) or 3542 (3 lead course) which leaves just two 
families =
> (the labelling I am using is out of simplicity and is not related to 
the =
> usual nomenclature). There are the regular leadheads:
> a 3524
> b 5432
> c 4253
> =20
> and the cyclic ones
> d 3452
> e 4523
> f 5234
> =20
> So there are 6 ie (n-2)! exactly as you said. 

you are missing
4532
5423

So there are three sets and 6 method types. For (n-1) prime, each set 
consists of (n-2) elements, so there are (n-3)!. More generally, the 
number in each set is the number of integers 1..n-2 that have no common 
factor with n-1.

> Also is it possible to have an odd bell cyclic method with the usual =

> symmetry (eg on 5 5.1.5.3.345 lh1 which is St Simons with 345 made at 
=
> the 1/2 lead gives lh 3452, it'snot very elegant but I just wrote it =

> down now). Just an aside and probably like the other rushed thoughts =

> incorrect!

It's only possible for n=5 - think what the lead end must be.

> I hope this has clarified the misunderstanding
> 

no

-- 
pabs