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A280552 Number of n X 6 0..1 arrays with no element equal to more than one of its horizontal and vertical neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

%I A280552 #7 Feb 13 2019 14:16:17
%S A280552 6,194,670,1666,3438,6502,11697,20440,35226,60300,102974,175746,
%T A280552 299975,512080,874058,1491286,2542606,4331134,7369949,12526488,
%U A280552 21265610,36058400,61069118,103308602,174569331,294669456,496887354,837059626
%N A280552 Number of n X 6 0..1 arrays with no element equal to more than one of its horizontal and vertical neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.
%H A280552 R. H. Hardin, <a href="/A280552/b280552.txt">Table of n, a(n) for n = 1..210</a>
%F A280552 Empirical: a(n) = 6*a(n-1) - 12*a(n-2) + 5*a(n-3) + 12*a(n-4) - 12*a(n-5) - 3*a(n-6) + 6*a(n-7) - a(n-9) for n>12.
%F A280552 Empirical g.f.: x*(6 + 158*x - 422*x^2 - 56*x^3 + 440*x^4 + 260*x^5 - 83*x^6 - 314*x^7 + 22*x^8 - 45*x^9 - 142*x^10 + 4*x^11) / ((1 - x)^3*(1 - x - x^2)^3). - _Colin Barker_, Feb 13 2019
%e A280552 Some solutions for n=4:
%e A280552 ..0..1..0..1..0..1. .0..1..0..1..1..0. .0..1..1..0..0..1. .0..0..1..0..0..0
%e A280552 ..1..0..1..0..1..0. .1..0..1..0..1..0. .0..1..0..1..0..1. .1..1..0..1..0..1
%e A280552 ..0..1..0..1..0..1. .0..1..0..1..0..1. .1..0..1..0..1..0. .0..0..1..0..1..0
%e A280552 ..0..0..1..1..0..1. .1..0..1..1..0..1. .1..0..1..0..1..0. .0..1..0..1..0..1
%Y A280552 Column 6 of A280554.
%K A280552 nonn
%O A280552 1,1
%A A280552 _R. H. Hardin_, Jan 05 2017