A193623 - OEIS

%I #10 Mar 12 2017 13:49:41

%S 1,1,3,44,14022,207392556,193491859167624,16390160979986065741152

%N Number of nonisomorphic Knuthian systems of order n^2.

%C See the pdf file of the Curtis et al. reference for precise definition.

%H Frank Curtis, John Drew, Chi-Kwong Li and Daniel Pragel, <a href="http://dx.doi.org/10.1016/j.jcta.2003.10.001">Central groupoids, central digraphs, and zero-one matrices A satisfying A^2 = J,</a> Journal of Combinatorial Theory, Series A, Volume 105 Issue 1, (2004) pp. 35-50.

%H F. Curtis, J. Drew, <a href="http://www.resnet.wm.edu/~cklixx/reu02.pdf">Central groupoids, central digraphs, and zero-one matrices A satisfying A^2=J</a>, (2002), expanded version.

%K nonn

%O 1,3

%A _N. J. A. Sloane_, Jul 31 2011