A301952 - OEIS

%I #4 Mar 29 2018 12:46:46

%S 0,5,20,123,680,4070,23565,138014,805249,4704141,27469522,160428571,

%T 936897912,5471539885,31953953498,186612354231,1089822896327,

%U 6364606387628,37169536347339,217071469820879,1267705419106309

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

%C Row 3 of A301951.

%H R. H. Hardin, <a href="/A301952/b301952.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 4*a(n-1) +12*a(n-2) -5*a(n-3) -14*a(n-4) +14*a(n-6) +4*a(n-7) -3*a(n-8) -5*a(n-9) +a(n-10) for n>12

%e Some solutions for n=5

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

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

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

%Y Cf. A301951.

%K nonn

%O 1,2

%A _R. H. Hardin_, Mar 29 2018