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A264667
Number of optimal solutions to the maximal number of diagonals problem studied in A264041.
1
2, 4, 28, 108, 2, 13968, 480, 7914054, 433284, 18726123500, 256, 178290006448984, 14454384, 6631290958957860856, 1401615406696, 941558205279187913101914, 1767136, 500995759754153499284692617816, 31163356068736, 984452644453618816989710782436259368
OFFSET
1,1
COMMENTS
Solutions that differ by a rotation and/or reflection are counted as different. - N. J. A. Sloane, Nov 20 2015
The paper by Boyland et al. gives a(13) = 14454384 and a(15) = 1401615406696. - Eric M. Schmidt, Aug 30 2017
LINKS
Peter Boyland, Gabriella Pintér, István Laukó, Ivan Roth, Jon E. Schoenfield, and Stephen Wasielewski, On the Maximum Number of Non-intersecting Diagonals in an Array, Journal of Integer Sequences, Vol. 20 (2017), Article 17.2.4.
EXAMPLE
For n=2 the 4 solutions are:
.\
\\
--
/.
//
--
\\
\.
--
//
./
--
where the dot indicates an empty cell.
CROSSREFS
Cf. A264041.
Sequence in context: A259375 A192374 A274526 * A356700 A357158 A259134
KEYWORD
nonn
AUTHOR
Rob Pratt, Nov 20 2015
EXTENSIONS
a(8)-a(13) from Andrew Howroyd, Feb 03 2018
a(14)-a(20) from Andrew Howroyd, Jun 22 2018
STATUS
approved