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Half the number of (n+1) X (n+1) 0..2 arrays with no 2 X 2 subblock having sum 4.
0

%I #7 May 08 2022 23:56:54

%S 31,3552,2214457,7635071835,144396520117972,15033760617564577257,

%T 8603578492435516321649249,27081302315719663051228636805358

%N Half the number of (n+1) X (n+1) 0..2 arrays with no 2 X 2 subblock having sum 4.

%C Diagonal of A183792.

%e Some solutions for 3 X 3

%e ..0..2..2....2..2..2....0..0..0....0..1..1....2..0..0....1..0..0....0..2..1

%e ..2..2..1....2..2..2....0..0..0....0..2..1....2..2..0....2..2..0....1..2..2

%e ..1..1..1....0..1..1....1..1..1....2..2..1....0..2..2....1..0..0....1..2..0

%Y Cf. A183792.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 07 2011