cp's OEIS Frontend

A220324 Equals two maps: number of n X 3 binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal and antidiagonal neighbors in a random 0..1 n X 3 array.

%I A220324 #8 Jul 31 2018 08:53:27
%S A220324 2,16,92,508,2788,15316,84196,462940,2545492,13996468,76959844,
%T A220324 423164812,2326777444,12793817140,70346976484,386803802332,
%U A220324 2126845944052,11694491219668,64302318307108,353567167818892,1944093859291588
%N A220324 Equals two maps: number of n X 3 binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal and antidiagonal neighbors in a random 0..1 n X 3 array.
%C A220324 Column 3 of A220328.
%H A220324 R. H. Hardin, <a href="/A220324/b220324.txt">Table of n, a(n) for n = 1..210</a>
%F A220324 Empirical: a(n) = 7*a(n-1) - 9*a(n-2) + 3*a(n-3) + 6*a(n-4).
%F A220324 Empirical g.f.: 2*x*(1 + x - x^2 + x^3) / (1 - 7*x + 9*x^2 - 3*x^3 - 6*x^4). - _Colin Barker_, Jul 31 2018
%e A220324 Some solutions for n=3:
%e A220324 ..0..1..1....0..1..1....0..1..1....0..0..1....0..0..0....0..0..1....0..0..0
%e A220324 ..1..0..1....0..1..0....0..0..0....0..1..1....1..1..0....1..0..1....0..0..1
%e A220324 ..0..0..0....1..1..0....0..0..0....0..0..0....1..1..0....0..0..0....0..1..0
%Y A220324 Cf. A220328.
%K A220324 nonn
%O A220324 1,1
%A A220324 _R. H. Hardin_, Dec 10 2012