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A281204 Number of n X 7 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards. 1

%I

%S 20,166,537,1358,3137,6838,14375,29416,58984,116466,227134,438532,

%T 839659,1596460,3017310,5673426,10619999,19801344,36791933,68149580,

%U 125882603,231941798,426388234,782226746,1432314394,2618121324,4778002317

%N Number of n X 7 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.

%H R. H. Hardin, <a href="/A281204/b281204.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 4*a(n-1) - 4*a(n-2) - 2*a(n-4) + 4*a(n-5) - 2*a(n-6) + 4*a(n-7) - a(n-8) - 2*a(n-10) - a(n-12).

%F Empirical g.f.: x*(20 + 86*x - 47*x^2 - 126*x^3 - 107*x^4 - 26*x^5 + 21*x^6 + 88*x^7 + 92*x^8 + 56*x^9 + 23*x^10 + 10*x^11) / ((1 - 2*x + x^2 - x^3)^2*(1 - x^2 - x^3)^2). - _Colin Barker_, Feb 18 2019

%e Some solutions for n=4:

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

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

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

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

%Y Column 7 of A281205.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 17 2017

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Last modified March 25 22:28 EDT 2019. Contains 321477 sequences. (Running on oeis4.)