A297507 - OEIS

%I #9 Feb 28 2019 16:21:09

%S 1,10,31,68,218,729,2097,6139,18932,57273,170792,514608,1554993,

%T 4677797,14071941,42401182,127713015,384477424,1157762858,3486768241,

%U 10499588277,31616525407,95208917296,286707283257,863361068252,2599853035248

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

%H R. H. Hardin, <a href="/A297507/b297507.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-1) - 2*a(n-2) + 9*a(n-3) - 6*a(n-4) - 8*a(n-5).

%F Empirical g.f.: x*(1 + 7*x + 3*x^2 - 14*x^3 - 8*x^4) / (1 - 3*x + 2*x^2 - 9*x^3 + 6*x^4 + 8*x^5). - _Colin Barker_, Feb 28 2019

%e Some solutions for n=7:

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

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

%Y Row 2 of A297506.

%K nonn

%O 1,2

%A _R. H. Hardin_, Dec 31 2017