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A193623 Number of nonisomorphic Knuthian systems of order n^2. 0
1, 1, 3, 44, 14022, 207392556, 193491859167624, 16390160979986065741152 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

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

LINKS

Table of n, a(n) for n=1..8.

Frank Curtis, John Drew, Chi-Kwong Li and Daniel Pragel, Central groupoids, central digraphs, and zero-one matrices A satisfying A^2 = J, Journal of Combinatorial Theory, Series A, Volume 105 Issue 1, (2004) pp. 35-50.

F. Curtis, J. Drew, Central groupoids, central digraphs, and zero-one matrices A satisfying A^2=J, (2002), expanded version.

CROSSREFS

Sequence in context: A011916 A337249 A259785 * A102811 A307007 A142600

Adjacent sequences:  A193620 A193621 A193622 * A193624 A193625 A193626

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Jul 31 2011

STATUS

approved

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Last modified October 26 06:08 EDT 2021. Contains 348257 sequences. (Running on oeis4.)