cp's OEIS Frontend

A221066 Sum of neighbor maps: number of n X 2 binary arrays indicating the locations of corresponding elements equal to the sum mod 4 of their king-move neighbors in a random 0..3 n X 2 array.

%I A221066 #8 Aug 03 2018 08:11:35
%S A221066 2,8,20,56,168,476,1364,3952,11360,32692,94236,271352,781432,2250892,
%T A221066 6482724,18670784,53775312,154880036,446074860,1284760776,3700290152,
%U A221066 10657349244,30694667380,88404940816,254618597952,733337259924
%N A221066 Sum of neighbor maps: number of n X 2 binary arrays indicating the locations of corresponding elements equal to the sum mod 4 of their king-move neighbors in a random 0..3 n X 2 array.
%C A221066 Column 2 of A221072.
%H A221066 R. H. Hardin, <a href="/A221066/b221066.txt">Table of n, a(n) for n = 1..210</a>
%F A221066 Empirical: a(n) = 2*a(n-1) + 2*a(n-2) + 4*a(n-3) - 5*a(n-4) - 6*a(n-5).
%F A221066 Empirical g.f.: 2*x*(1 + x)*(1 + x - x^2 - 3*x^3) / (1 - 2*x - 2*x^2 - 4*x^3 + 5*x^4 + 6*x^5). - _Colin Barker_, Aug 03 2018
%e A221066 Some solutions for n=3:
%e A221066 ..0..0....0..0....1..1....0..1....0..1....0..0....0..1....0..0....0..0....1..0
%e A221066 ..1..0....0..1....0..0....0..0....1..0....0..0....0..1....1..1....1..0....0..0
%e A221066 ..0..1....1..0....0..0....0..1....0..0....1..1....0..0....1..1....1..0....0..1
%Y A221066 Cf. A221072.
%K A221066 nonn
%O A221066 1,1
%A A221066 _R. H. Hardin_, Dec 31 2012