A217230 - OEIS

%I #9 Sep 13 2013 21:55:41

%S 0,1,47,5167,1950380,2709368919

%N Number of triangular nXnXn arrays of occupancy after each element moves to some neighbor but without 2-loops and with no occupancy greater than 4.

%C Column 4 of A217232.

%e Some solutions for n=4

%e .....1........0........0........0........0........0........0........1

%e ....2.1......1.1......2.2......2.0......1.1......1.0......0.2......1.2

%e ...2.0.1....2.1.0....0.2.3....1.2.0....0.2.0....0.4.1....3.1.1....1.0.1

%e ..0.2.1.0..0.3.2.0..0.1.0.0..0.3.1.1..0.3.2.1..1.2.1.0..1.1.0.1..1.2.0.1

%K nonn,hard,more

%O 1,3

%A _R. H. Hardin_, Sep 28 2012