A223410 - OEIS

A223410

4X4X4 triangular graph without horizontal edges coloring a rectangular array: number of nX3 0..9 arrays where 0..9 label nodes of a graph with edges 0,1 0,2 1,3 1,4 2,4 2,5 3,6 3,7 4,7 4,8 5,8 5,9 and every array movement to a horizontal or vertical neighbor moves along an edge of this graph

%I #4 Mar 20 2013 05:04:27

%S 66,780,10496,139552,1905248,25615364,350374768,4718334196,

%T 64553618848,869537910656,11896879751308,160257988295804,

%U 2192633026299036,29536279905976948,404112522712546100,5443681701489022792

%N 4X4X4 triangular graph without horizontal edges coloring a rectangular array: number of nX3 0..9 arrays where 0..9 label nodes of a graph with edges 0,1 0,2 1,3 1,4 2,4 2,5 3,6 3,7 4,7 4,8 5,8 5,9 and every array movement to a horizontal or vertical neighbor moves along an edge of this graph

%C Column 3 of A223415

%H R. H. Hardin, <a href="/A223410/b223410.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 246*a(n-2) -12495*a(n-4) +213864*a(n-6) -1242839*a(n-8) +3210236*a(n-10) -3946254*a(n-12) +2244580*a(n-14) -563760*a(n-16) +50544*a(n-18) for n>19

%e Some solutions for n=3

%e ..2..4..8....1..4..2....8..4..2....4..2..4....1..0..2....5..9..5....4..2..4

%e ..0..2..5....4..8..4....5..2..5....7..4..2....4..1..0....8..5..9....7..4..1

%e ..2..0..2....2..4..1....8..5..9....4..1..4....2..4..1....5..9..5....3..1..4

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 20 2013