A268143 - OEIS

A268143

Number of 3 X n arrays containing n copies of 0..3-1 with every element equal to at least one diagonal or antidiagonal neighbor and the top left element equal to 0.

%I #8 Apr 28 2021 12:52:49

%S 0,0,0,8,32,238,1488,9778,91628,685364,5183732,43292440,341958992,

%T 2698310688,22015262376,177423576662,1428012268840,11630157575168,

%U 94604167006872,769682941957332,6291338814803772,51481101154395306

%N Number of 3 X n arrays containing n copies of 0..3-1 with every element equal to at least one diagonal or antidiagonal neighbor and the top left element equal to 0.

%C Row 3 of A268142.

%H R. H. Hardin, <a href="/A268143/b268143.txt">Table of n, a(n) for n = 1..52</a>

%e Some solutions for n=4

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

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

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

%Y Cf. A268142.

%K nonn

%O 1,4

%A _R. H. Hardin_, Jan 27 2016