cp's OEIS Frontend

A268997 Number of 3 X n binary arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two not more than once.

%I A268997 #7 Jan 18 2019 06:33:30
%S A268997 8,41,174,805,3331,14080,57287,232449,928886,3688159,14524152,
%T A268997 56872865,221485093,858684462,3315594029,12757162785,48929395140,
%U A268997 187135343189,713890088738,2717075148077,10319450344743,39117842242220
%N A268997 Number of 3 X n binary arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two not more than once.
%H A268997 R. H. Hardin, <a href="/A268997/b268997.txt">Table of n, a(n) for n = 1..210</a>
%F A268997 Empirical: a(n) = 3*a(n-1) + 12*a(n-2) - 16*a(n-3) - 62*a(n-4) - 34*a(n-5) + 16*a(n-6) + 12*a(n-7) - a(n-8) - a(n-9).
%F A268997 Empirical g.f.: x*(8 + 17*x - 45*x^2 - 81*x^3 - 20*x^4 + 25*x^5 + 9*x^6 - 2*x^7 - x^8) / ((1 + x)*(1 - 2*x - 6*x^2 + x^4)^2). - _Colin Barker_, Jan 18 2019
%e A268997 Some solutions for n=4:
%e A268997 ..1..0..1..1. .0..0..0..0. .0..1..0..0. .0..0..0..1. .1..0..1..0
%e A268997 ..0..0..0..0. .0..0..1..0. .0..1..0..1. .1..0..0..1. .1..0..1..0
%e A268997 ..1..0..0..0. .0..1..0..1. .0..1..0..1. .0..1..0..1. .1..0..1..1
%Y A268997 Row 3 of A268995.
%K A268997 nonn
%O A268997 1,1
%A A268997 _R. H. Hardin_, Feb 17 2016