cp's OEIS Frontend

A208170 Number of n X 3 0..3 arrays with new values 0..3 introduced in row major order and no element equal to more than one of its immediate leftward or upward neighbors.

%I A208170 #8 Jun 29 2018 06:03:00
%S A208170 5,159,8469,473928,26625693,1496307201,84091222866,4725865313907,
%T A208170 265590215430897,14925978329967384,838829205068709369,
%U A208170 47141595663874099773,2649323638611897879018,148890075596000256587991
%N A208170 Number of n X 3 0..3 arrays with new values 0..3 introduced in row major order and no element equal to more than one of its immediate leftward or upward neighbors.
%C A208170 Column 3 of A208175.
%H A208170 R. H. Hardin, <a href="/A208170/b208170.txt">Table of n, a(n) for n = 1..210</a>
%F A208170 Empirical: a(n) = 62*a(n-1) - 333*a(n-2) + 396*a(n-3) - 135*a(n-4) for n>5.
%F A208170 Empirical g.f.: x*(5 - 151*x + 276*x^2 - 183*x^3 + 45*x^4) / ((1 - 5*x + 3*x^2)*(1 - 57*x + 45*x^2)). - _Colin Barker_, Jun 29 2018
%e A208170 Some solutions for n=4:
%e A208170 ..0..0..1....0..1..2....0..1..1....0..0..1....0..1..0....0..0..0....0..0..0
%e A208170 ..0..1..0....3..0..1....0..0..0....0..2..0....0..2..2....0..1..0....1..1..0
%e A208170 ..0..0..1....2..0..0....0..1..1....1..2..1....1..2..1....2..1..1....0..1..0
%e A208170 ..1..1..0....1..3..0....0..2..1....3..0..0....1..3..2....0..2..1....0..1..0
%Y A208170 Cf. A208175.
%K A208170 nonn
%O A208170 1,1
%A A208170 _R. H. Hardin_, Feb 24 2012