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Number of n X 5 0..1 arrays with every 1 horizontally or antidiagonally adjacent to 2 neighboring 1s.
1

%I #7 Feb 26 2019 11:50:48

%S 1,4,9,21,49,114,266,620,1446,3372,7864,18340,42772,99752,232640,

%T 542560,1265352,2951040,6882384,16051024,37434032,87303264,203607776,

%U 474851968,1107444896,2582771648,6023513600,14047976768,32762547648,76408478336

%N Number of n X 5 0..1 arrays with every 1 horizontally or antidiagonally adjacent to 2 neighboring 1s.

%H R. H. Hardin, <a href="/A297296/b297296.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 2*a(n-1) + 2*a(n-2) - 2*a(n-3) - 2*a(n-4) for n>5.

%F Empirical g.f.: x*(1 + x)*(1 + x - 2*x^2 - x^3) / (1 - 2*x - 2*x^2 + 2*x^3 + 2*x^4). - _Colin Barker_, Feb 26 2019

%e Some solutions for n=5:

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

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

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

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

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

%Y Column 5 of A297299.

%K nonn

%O 1,2

%A _R. H. Hardin_, Dec 27 2017