|
%I #7 Jan 15 2019 14:19:06
%S 0,20,84,501,2190,9996,42362,178400,732378,2974934,11933578,47466417,
%T 187325260,734639334,2865135348,11121381104,42989239524,165564387000,
%U 635557701344,2432620417837,9286486715514,35366757558512,134400104565934
%N Number of 3 X n binary arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two exactly once.
%H R. H. Hardin, <a href="/A268888/b268888.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) + 12*a(n-2) - 16*a(n-3) - 62*a(n-4) - 34*a(n-5) + 16*a(n-6) + 12*a(n-7) - a(n-8) - a(n-9).
%F Empirical g.f.: x^2*(2 - x)*(10 + 17*x + 13*x^2 + 6*x^3 + 2*x^4) / ((1 + x)*(1 - 2*x - 6*x^2 + x^4)^2). - _Colin Barker_, Jan 15 2019
%e Some solutions for n=4:
%e ..0..0..1..0. .0..0..0..0. .0..0..0..1. .0..0..0..0. .0..1..0..1
%e ..1..0..0..0. .0..0..0..1. .1..1..0..1. .0..0..1..1. .0..0..0..1
%e ..1..0..1..1. .1..1..0..0. .0..0..0..0. .1..0..0..1. .0..0..1..0
%Y Row 3 of A268886.
%K nonn
%O 1,2
%A _R. H. Hardin_, Feb 15 2016
| 