cp's OEIS Frontend

A208394 Number of 3 X n 0..2 arrays with new values 0..2 introduced in row major order and no element equal to more than two of its immediate leftward or upward or right-upward antidiagonal neighbors.

%I A208394 #9 Jul 02 2018 10:16:01
%S A208394 5,122,3042,76806,1937736,48890520,1233536544,31122868320,
%T A208394 785248636032,19812294175104,499876067713536,12612173071468032,
%U A208394 318212692821854208,8028697140386371584,202568845385856983040,5110933493125207056384
%N A208394 Number of 3 X n 0..2 arrays with new values 0..2 introduced in row major order and no element equal to more than two of its immediate leftward or upward or right-upward antidiagonal neighbors.
%C A208394 Row 3 of A208392.
%H A208394 R. H. Hardin, <a href="/A208394/b208394.txt">Table of n, a(n) for n = 1..210</a>
%F A208394 Empirical: a(n) = 22*a(n-1) + 80*a(n-2) + 40*a(n-3) - 48*a(n-4) for n>6.
%F A208394 Empirical g.f.: x*(5 + 12*x - 42*x^2 - 78*x^3 + 4*x^4 + 24*x^5) / ((1 + 2*x)*(1 - 24*x - 32*x^2 + 24*x^3)). - _Colin Barker_, Jul 02 2018
%e A208394 Some solutions for n=4:
%e A208394 ..0..1..2..1....0..0..1..2....0..0..1..2....0..0..0..1....0..0..0..0
%e A208394 ..2..0..0..1....0..2..1..0....0..2..0..2....1..1..1..0....0..1..0..0
%e A208394 ..0..2..0..1....2..1..2..1....2..2..0..2....0..1..2..2....0..1..2..0
%Y A208394 Cf. A208392.
%K A208394 nonn
%O A208394 1,1
%A A208394 _R. H. Hardin_, Feb 25 2012