cp's OEIS Frontend

A221241 Number of n X 3 arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor.

%I A221241 #8 Aug 04 2018 13:42:17
%S A221241 2,50,1056,21660,441720,8997120,183206016,3730330800,75953515968,
%T A221241 1546488223200,31487986033920,641125466910720,13053925809145728,
%U A221241 265790370894192000,5411745241852207104,110188290202715208960
%N A221241 Number of n X 3 arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor.
%C A221241 Column 3 of A221245.
%H A221241 R. H. Hardin, <a href="/A221241/b221241.txt">Table of n, a(n) for n = 1..119</a>
%F A221241 Empirical: a(n) = 30*a(n-1) - 222*a(n-2) + 540*a(n-3) - 324*a(n-4).
%F A221241 Empirical g.f.: 2*(1 - 5*x) / (1 - 30*x + 222*x^2 - 540*x^3 + 324*x^4). - _Colin Barker_, Aug 04 2018
%e A221241 Some solutions for n=3:
%e A221241 ..1..1..0....0..0..1....0..2..2....0..0..0....2..1..0....0..3..0....0..4..1
%e A221241 ..1..1..1....1..4..0....0..4..1....0..5..1....0..4..0....1..3..0....0..2..0
%e A221241 ..0..4..0....0..2..1....0..0..0....0..1..2....1..1..0....2..0..0....1..0..1
%Y A221241 Cf. A221245.
%K A221241 nonn
%O A221241 1,1
%A A221241 _R. H. Hardin_, Jan 06 2013