cp's OEIS Frontend

A222440 Number of n X 4 0..3 arrays with entries increasing mod 4 by 0, 1 or 2 rightwards and downwards, starting with upper left zero.

%I A222440 #7 Mar 15 2018 10:10:29
%S A222440 27,1029,39285,1500183,57289767,2187822609,83550197745,3190677470643,
%T A222440 121847980727187,4653221950068669,177700725073710285,
%U A222440 6786168386579878383,259155281174281941087,9896815984320245625609,377947021506548282896905
%N A222440 Number of n X 4 0..3 arrays with entries increasing mod 4 by 0, 1 or 2 rightwards and downwards, starting with upper left zero.
%C A222440 Column 4 of A222444.
%H A222440 R. H. Hardin, <a href="/A222440/b222440.txt">Table of n, a(n) for n = 1..210</a>
%F A222440 Empirical: a(n) = 45*a(n-1) - 267*a(n-2) + 263*a(n-3).
%F A222440 Empirical g.f.: 3*x*(9 - 62*x + 63*x^2) / (1 - 45*x + 267*x^2 - 263*x^3). - _Colin Barker_, Mar 15 2018
%e A222440 Some solutions for n=3:
%e A222440 ..0..2..2..0....0..2..3..0....0..2..2..3....0..0..2..2....0..2..3..1
%e A222440 ..1..2..0..1....1..2..0..1....1..3..0..0....2..0..0..2....2..0..0..1
%e A222440 ..2..3..1..2....2..2..2..2....2..0..1..2....2..2..2..3....3..0..0..2
%Y A222440 Cf. A222444.
%K A222440 nonn
%O A222440 1,1
%A A222440 _R. H. Hardin_, Feb 20 2013