A269048 - OEIS

%I #7 Jan 18 2019 16:24:54

%S 60,360,3078,24192,183072,1350672,9779808,69793968,492374976,

%T 3441051984,23861339424,164375084016,1125975740544,7675458754704,

%U 52099028628960,352309891913520,2374503933353280,15956129491021776,106934858162261664

%N Number of n X 4 0..2 arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling two not more than once.

%H R. H. Hardin, <a href="/A269048/b269048.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 14*a(n-1) - 57*a(n-2) + 56*a(n-3) - 16*a(n-4) for n>5.

%F Empirical g.f.: 6*x*(10 - 80*x + 243*x^2 - 290*x^3 + 105*x^4) / (1 - 7*x + 4*x^2)^2. - _Colin Barker_, Jan 18 2019

%e Some solutions for n=4:

%e ..0..1..2..0. .2..1..2..1. .1..2..1..2. .0..0..0..1. .2..1..1..2

%e ..0..1..0..1. .2..1..0..1. .1..2..1..2. .0..0..0..0. .2..2..2..2

%e ..0..0..0..0. .2..1..2..0. .2..2..2..2. .0..0..0..1. .2..2..2..1

%e ..0..1..0..0. .2..1..0..1. .1..1..2..1. .1..0..0..0. .2..1..2..1

%Y Column 4 of A269052.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 18 2016