1,4

Urzua abstract: "We start by showing a one to one correspondence between arrangements of d lines in P^2 and lines in P^{d-2}. Then we apply this to classify (3,q)-nets on P^2 for all 2 <= q <= 6. For the new case q=6, we have a priori twelve possible cases, but we obtain that only six of them are realizable on P^2 over C. We give equations for the lines defining these nets. We also construct a three dimensional family of (3,8)-nets corresponding to the multiplication table of the Quaternion group. After that, we define more general arrangements of curves and relate them, via moduli spaces of pointed stable curves of genus zero, to curves in P^{d-2}. Then, we prove that there is a one to one correspondence between these more general arrangements of d curves and certain curves in P^{d-2}. As a corollary, we recover the one to one correspondence for line arrangements. This more general setting not only generalizes line arrangements but also shows the ideas behind what we did in that case." - Jonathan Vos Post (jvospost3(AT)gmail.com), Apr 05 2007

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

F. Harary and E. M. Palmer, Graphical Enumeration, Academic Press, NY, 1973, p. 231.

I. M. Wanless, A generalization of transversals for Latin squares, Electron. J. Combin., 9 (2002), #R12.

A. Hulpke, P. Kaski and P. R. J. Ostergard, The number of Latin squares of order 11, Preprint, 2009.

B. D. McKay, Latin Squares (has list of all such squares)

B. D. McKay, A. Meynert and W. Myrvold, Small Latin Squares, Quasigroups and Loops, J. Combin. Designs, to appear (2005).

B. D. McKay and E. Rogoyski, Latin squares of order ten, Electron. J. Combinatorics, 2 (1995) #N3.

Index entries for sequences related to Latin squares and rectangles

Giancarlo Urzua, On line arrangements with applications to 3-nets (see page 9).

Cf. A000315, A002860, A040082.

Sequence in context: A032320 A032227 A032069 this_sequence A032152 A032057 A130718

Adjacent sequences: A003087 A003088 A003089 this_sequence A003091 A003092 A003093

nonn,nice,hard

N. J. A. Sloane (njas(AT)research.att.com).

Two more terms (from the McKay-Meynert-Myrvold article) from Richard Bean (rwb(AT)eskimo.com), Feb 17 2004

There are 2036029552582883134196099 main classes of Latin squares of order 11. - Petteri Kaski (petteri.kaski(AT)cs.helsinki.fi), Sep 18 2009

arXiv URL replaced by its non-cached version - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 23 2009