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Number of n X n 0..1 arrays with every element equal to 0, 2 or 3 horizontally or vertically adjacent elements, with upper left element zero.
0

%I #6 Aug 20 2020 11:46:01

%S 1,2,2,25,330,8888,591585,83224304,23865691820,14092825824108

%N Number of n X n 0..1 arrays with every element equal to 0, 2 or 3 horizontally or vertically adjacent elements, with upper left element zero.

%C Diagonal of A301608.

%e Some solutions for n=5

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

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

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

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

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

%Y Cf. A301608.

%K nonn

%O 1,2

%A _R. H. Hardin_, Mar 24 2018