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%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