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Number of 2n X 2n Takuzu grids.
1

%I #17 Sep 03 2017 21:28:42

%S 1,2,72,4140,4111116,48183195384

%N Number of 2n X 2n Takuzu grids.

%C A Takuzu grid is a 2n X 2n zero-one matrix with the following properties:

%C 1. Every row and every column has n zeros and n ones.

%C 2. No row or column has three consecutive zeros or three consecutive ones.

%C 3. All rows are distinct, and all columns are distinct (but a row may be the same as a column).

%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Takuzu">Takuzu</a>

%e The following is a 4 X 4 Takuzu grid:

%e [ 0 1 1 0 ]

%e [ 1 0 0 1 ]

%e [ 0 0 1 1 ]

%e [ 1 1 0 0 ]

%Y Cf. A058527.

%Y Number of possible rows equals A003440.

%K nonn,more

%O 0,2

%A _Brian Kell_, Dec 30 2014

%E a(5) from _Frans J. Faase_, Dec 14 2015