various

[N. J. A. Sloane]

1. Let T(n,k) be the number of ordered k-tuples 
of permutations of n letters which commute with each other.

That is, T(n,k) = number of (p_1, ..., p_k) , all p_i in Symm(n),
such that p_i p_j = p_j p_i

John McKay said the sequence T(n,3) is in the OEIS
but that the others should be added.

(I don't know the sequence number for T(n,3).)

Of course the triangle T(n,k) should also be added


2.  I will be on holiday for the next week or 10 days,
so there will no more updates until I get back
All messages will be saved.


3. Jeff Lagarias and I wrote up our paper on approximate
squaring (it's on my home page), which is related to
a number of sequences.

Neil Sloane

 Neil J. A. Sloane
 AT&T Shannon Labs, Room C233, 
 180 Park Avenue, Florham Park, NJ 07932-0971
 Email: njas at research.att.com
 Office: 973 360 8415; fax: 973 360 8178
 Home page: http://www.research.att.com/~njas/