Colin Mallows's problems
N. J. A. Sloane
njas at research.att.com
Fri Jun 10 16:23:39 CEST 2005
My former colleague Colin Mallows sent me this:
You asked for problems. I would very much like to know the answers
to the following two; they may have been done by someone, but I don't
think they are in the OEIS.
A039622 gives the number of ways of filling an nxn matrix with the integers
1:n^2 so that each row and column is in increasing order. What about a
mxn matrix? (for 2xn we get the Catalan numbers).
For each m,n, how many of these arrangments can be realised as the ordering
of numbers of the form x_i + y_j?
Colin Mallows (colinm at research.avayalabs.com)
If any seqfans get interested in these questions,
please send me copies of any emails. - Neil Sloane
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