cp's OEIS Frontend

A221122 Number of n X 4 arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor.

%I A221122 #10 Aug 03 2018 21:08:21
%S A221122 21,1950,179300,16436223,1506094707,138001217828,12644783009532,
%T A221122 1158616222843158,106161685080363377,9727382617196220288,
%U A221122 891300589691816054472,81668088157651470747218,7483083373227566657384892
%N A221122 Number of n X 4 arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor.
%C A221122 Column 4 of A221125.
%H A221122 R. H. Hardin, <a href="/A221122/b221122.txt">Table of n, a(n) for n = 1..18</a>
%F A221122 Empirical: a(n) = 109*a(n-1) - 1680*a(n-2) + 8230*a(n-3) - 13300*a(n-4) + 2025*a(n-5) for n>6.
%F A221122 Empirical g.f.: x*(21 - 339*x + 2030*x^2 - 4307*x^3 + 1200*x^4 + 2880*x^5) / (1 - 109*x + 1680*x^2 - 8230*x^3 + 13300*x^4 - 2025*x^5). - _Colin Barker_, Aug 03 2018
%e A221122 Some solutions for n=3:
%e A221122   1 1 1 0     0 3 1 1     0 2 0 2     1 1 0 1     1 0 2 0
%e A221122   1 2 1 1     1 1 1 2     1 3 0 1     0 1 3 0     0 3 4 0
%e A221122   0 1 3 0     0 1 0 1     0 0 1 2     0 3 1 1     0 1 1 0
%Y A221122 Cf. A221125.
%K A221122 nonn
%O A221122 1,1
%A A221122 _R. H. Hardin_, Jan 02 2013