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%I #8 Feb 23 2019 07:23:40
%S 1,4,8,17,46,114,289,757,1964,5118,13391,35008,91589,239740,627506,
%T 1642656,4300361,11258087,29473546,77162161,202011991,528872756,
%U 1384604934,3624939359,9490209947,24845686106,65046840605,170294825972
%N Number of n X 2 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 2 or 3 neighboring 1s.
%H R. H. Hardin, <a href="/A296399/b296399.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) - a(n-2) + 2*a(n-3) - 6*a(n-4) + 3*a(n-5) - 2*a(n-6) - a(n-7) - 2*a(n-8) + a(n-9).
%F Empirical g.f.: x*(1 + x - 3*x^2 - 5*x^3 + x^4 - 2*x^5 - 3*x^6 - x^7 + x^8) / ((1 - 3*x + x^2)*(1 - 2*x^3 - x^5 - x^6 - x^7)). - _Colin Barker_, Feb 23 2019
%e Some solutions for n=7:
%e ..0..0. .0..0. .1..1. .1..1. .1..1. .1..1. .0..1. .0..0. .0..0. .1..1
%e ..1..1. .0..0. .1..0. .1..1. .1..0. .1..1. .1..1. .0..1. .0..1. .1..0
%e ..1..0. .1..1. .1..1. .0..0. .1..1. .0..0. .1..0. .1..1. .1..1. .0..0
%e ..1..1. .1..0. .1..1. .0..0. .1..0. .0..1. .0..0. .0..1. .1..0. .0..1
%e ..1..0. .1..0. .0..0. .0..0. .0..0. .1..1. .0..1. .1..1. .1..1. .1..1
%e ..1..1. .1..1. .1..1. .1..1. .0..0. .0..1. .1..1. .0..0. .1..0. .0..1
%e ..1..1. .1..0. .1..1. .1..1. .0..0. .1..1. .0..0. .0..0. .0..0. .1..1
%Y Column 2 of A296405.
%K nonn
%O 1,2
%A _R. H. Hardin_, Dec 11 2017
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