cp's OEIS Frontend

A219143 Unchanging value maps: number of 2 X n binary arrays indicating the locations of corresponding elements unequal to no horizontal, diagonal or antidiagonal neighbor in a random 0..2 2 X n array.

%I A219143 #7 Mar 11 2018 09:54:48
%S A219143 1,6,18,39,96,225,543,1293,3096,7392,17673,42228,100929,241197,576441,
%T A219143 1377606,3292314,7868187,18803964,44939013,107398431,256668285,
%U A219143 613403916,1465955712,3503443917,8372776200,20009848437,47820940581,114285841233
%N A219143 Unchanging value maps: number of 2 X n binary arrays indicating the locations of corresponding elements unequal to no horizontal, diagonal or antidiagonal neighbor in a random 0..2 2 X n array.
%C A219143 Row 2 of A219142.
%H A219143 R. H. Hardin, <a href="/A219143/b219143.txt">Table of n, a(n) for n = 1..210</a>
%F A219143 Empirical: a(n) = 2*a(n-1) + a(n-2) - a(n-3) + 2*a(n-4) for n>5.
%F A219143 Empirical g.f.: x*(1 + 4*x + 5*x^2 - 2*x^3 + 4*x^4) / (1 - 2*x - x^2 + x^3 - 2*x^4). - _Colin Barker_, Mar 11 2018
%e A219143 Some solutions for n=3:
%e A219143 ..1..0..0....0..0..0....0..0..1....0..0..1....0..0..1....1..0..1....1..1..1
%e A219143 ..0..0..1....1..0..0....1..0..0....1..0..1....0..0..0....0..0..0....1..1..1
%Y A219143 Cf. A219142.
%K A219143 nonn
%O A219143 1,2
%A A219143 _R. H. Hardin_, Nov 12 2012