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Number of n X n 0..2 arrays with no element equal to any value at offset (-1,0) (0,-1) or (-2,-2) and new values introduced in order 0..2.
1

%I #7 Apr 19 2020 23:49:23

%S 1,3,19,118,1085,14414,289494,8474549,367622030,23768683063,

%T 2264991184042,321683159101264,67771416854833971,21147805661160867290,

%U 9831636745023577739551,6777168866402222336954286

%N Number of n X n 0..2 arrays with no element equal to any value at offset (-1,0) (0,-1) or (-2,-2) and new values introduced in order 0..2.

%C Diagonal of A274858.

%H R. H. Hardin, <a href="/A274852/b274852.txt">Table of n, a(n) for n = 1..17</a>

%e Some solutions for n=4

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

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

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

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

%Y Cf. A274858.

%K nonn

%O 1,2

%A _R. H. Hardin_, Jul 09 2016