cp's OEIS Frontend

A221408 T(n,k)=Number of nXk arrays of occupancy after each element stays put or moves to some horizontal or vertical neighbor, with every occupancy equal to zero or two.

%I A221408 #6 Jul 23 2025 01:53:22
%S A221408 0,2,2,0,6,0,4,16,16,4,0,44,0,44,0,8,120,436,436,120,8,0,328,0,4518,0,
%T A221408 328,0,16,896,12668,47156,47156,12668,896,16,0,2448,0,492102,0,492102,
%U A221408 0,2448,0,32,6688,368268,5133044,18852560,18852560,5133044,368268,6688,32
%N A221408 T(n,k)=Number of nXk arrays of occupancy after each element stays put or moves to some horizontal or vertical neighbor, with every occupancy equal to zero or two.
%C A221408 Table starts
%C A221408 ..0.....2........0.........4..........0...........8...........0............16
%C A221408 ..2.....6.......16........44........120.........328.........896..........2448
%C A221408 ..0....16........0.......436..........0.......12668...........0........368268
%C A221408 ..4....44......436......4518......47156......492102.....5133044......53529806
%C A221408 ..0...120........0.....47156..........0....18852560...........0....7505597654
%C A221408 ..8...328....12668....492102...18852560...722442370.27665242848.1058237377670
%C A221408 ..0...896........0...5133044..........0.27665242848
%C A221408 .16..2448...368268..53529806.7505597654
%C A221408 ..0..6688........0.558164472
%C A221408 .32.18272.10705360
%C A221408 ..0.49920
%C A221408 .64
%H A221408 R. H. Hardin, <a href="/A221408/b221408.txt">Table of n, a(n) for n = 1..84</a>
%e A221408 Some solutions for n=3 k=4
%e A221408 ..2..2..0..2....2..0..2..0....2..0..2..2....2..0..2..0....0..2..2..0
%e A221408 ..0..0..0..0....0..2..2..0....0..0..2..0....2..2..2..0....2..0..0..0
%e A221408 ..2..2..2..0....2..0..0..2....0..2..2..0....0..0..2..0....2..2..0..2
%Y A221408 Column 1 is A077957
%Y A221408 Column 2 is A002605(n+1)
%K A221408 nonn,tabl
%O A221408 1,2
%A A221408 _R. H. Hardin_ Jan 15 2013