cp's OEIS Frontend

A208388 Number of n X 4 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 A208388 #8 Jul 02 2018 09:13:05
%S A208388 14,1017,76806,5800644,438083928,33085555344,2498731184736,
%T A208388 188712490047552,14252194920963456,1076373164351510784,
%U A208388 81291281473560135168,6139387958073915884544,463666998680569442359296
%N A208388 Number of n X 4 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 A208388 Column 4 of A208392.
%H A208388 R. H. Hardin, <a href="/A208388/b208388.txt">Table of n, a(n) for n = 1..210</a>
%F A208388 Empirical: a(n) = 76*a(n-1) - 36*a(n-2) for n>3.
%F A208388 Empirical g.f.: x*(14 - 47*x + 18*x^2) / (1 - 76*x + 36*x^2). - _Colin Barker_, Jul 02 2018
%e A208388 Some solutions for n=4:
%e A208388 ..0..1..2..1....0..0..0..0....0..0..0..0....0..0..0..0....0..1..2..1
%e A208388 ..2..2..0..0....0..1..1..0....1..1..0..2....1..2..2..2....2..2..1..2
%e A208388 ..0..2..2..0....0..1..0..2....2..0..1..0....1..2..1..1....0..2..2..2
%e A208388 ..0..1..0..1....2..2..0..1....1..2..0..2....1..2..1..1....0..0..2..1
%Y A208388 Cf. A208392.
%K A208388 nonn
%O A208388 1,1
%A A208388 _R. H. Hardin_, Feb 25 2012