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Number of nX3 0..1 arrays with each 1 horizontally or vertically adjacent to 1 or 3 1s.
1

%I #4 Nov 14 2017 11:14:00

%S 3,11,33,114,377,1249,4151,13765,45704,151720,503627,1671816,5549529,

%T 18421629,61150537,202988906,673820905,2236745220,7424865048,

%U 24646804474,81814951110,271584345815,901522957697,2992601212814,9933925633736

%N Number of nX3 0..1 arrays with each 1 horizontally or vertically adjacent to 1 or 3 1s.

%C Column 3 of A295097.

%H R. H. Hardin, <a href="/A295092/b295092.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-1) +3*a(n-3) -a(n-4) +11*a(n-5) -5*a(n-6) -14*a(n-8) -4*a(n-9) -9*a(n-10) -a(n-11) +a(n-12) +4*a(n-14) +a(n-16)

%e Some solutions for n=5

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

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

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

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

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

%Y Cf. A295097.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 14 2017