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A281057 Number of 2 X n 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

%I A281057 #8 Feb 15 2019 08:11:02
%S A281057 0,1,6,34,104,251,535,1076,2090,3956,7353,13474,24417,43846,78142,
%T A281057 138374,243687,427098,745403,1296072,2246018,3880504,6686165,11491746,
%U A281057 19706373,33722458,57596214,98195818,167136611,284039674,482013727,816869276
%N A281057 Number of 2 X n 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.
%H A281057 R. H. Hardin, <a href="/A281057/b281057.txt">Table of n, a(n) for n = 1..210</a>
%F A281057 Empirical: a(n) = 5*a(n-1) - 7*a(n-2) - 2*a(n-3) + 10*a(n-4) - 2*a(n-5) - 5*a(n-6) + a(n-7) + a(n-8) for n>14.
%F A281057 Empirical g.f.: x^2*(1 + x + 11*x^2 - 22*x^3 - 29*x^4 + 18*x^5 + 43*x^6 + 14*x^7 - 31*x^8 - 13*x^9 + 8*x^10 + 2*x^11 - x^12) / ((1 - x)^2*(1 - x - x^2)^3). - _Colin Barker_, Feb 15 2019
%e A281057 Some solutions for n=4:
%e A281057 ..0..0..0..1. .0..1..1..1. .0..1..1..0. .0..0..1..1. .0..1..0..0
%e A281057 ..0..1..1..0. .0..0..1..0. .0..0..0..0. .1..1..0..1. .0..0..1..0
%Y A281057 Row 2 of A281056.
%K A281057 nonn
%O A281057 1,3
%A A281057 _R. H. Hardin_, Jan 13 2017