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%I #8 Mar 01 2019 06:20:52
%S 3,11,36,102,370,1243,3854,13078,43861,141109,468638,1561065,5101698,
%T 16842125,55830567,183595621,605376713,2001499842,6596762626,
%U 21752445702,71828204711,236917416288,781388833534,2578812375049,8507768092491
%N Number of n X 3 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1 or 4 neighboring 1s.
%H R. H. Hardin, <a href="/A297577/b297577.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = a(n-1) + 2*a(n-2) + 19*a(n-3) + 4*a(n-4) - 17*a(n-5) - 8*a(n-6).
%F Empirical g.f.: x*(3 + 8*x + 19*x^2 - 13*x^3 - 25*x^4 - 8*x^5) / ((1 - x)*(1 - 2*x^2 - 21*x^3 - 25*x^4 - 8*x^5)). - _Colin Barker_, Mar 01 2019
%e Some solutions for n=7:
%e ..0..0..0. .1..0..1. .0..0..0. .0..0..0. .0..0..0. .1..1..0. .0..0..0
%e ..0..1..1. .1..1..1. .0..1..1. .1..0..1. .1..0..0. .0..0..0. .0..0..0
%e ..0..0..0. .0..0..0. .0..0..0. .0..1..1. .1..1..0. .1..0..1. .0..1..1
%e ..1..0..1. .0..1..0. .0..0..1. .0..0..1. .1..0..1. .1..1..1. .0..0..0
%e ..1..1..1. .1..0..0. .1..1..1. .0..0..0. .1..0..1. .0..0..0. .1..0..1
%e ..0..0..0. .1..0..1. .0..0..1. .0..1..0. .1..1..0. .0..0..1. .0..1..1
%e ..0..1..1. .1..1..1. .0..0..0. .0..0..1. .1..0..0. .0..1..0. .0..0..1
%Y Column 3 of A297582.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jan 01 2018
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