A185819 - OEIS

%I #7 Mar 31 2012 12:36:03

%S 1,76,1584,49036,1266624,35446376,956312244,26231137608,714107480512,

%T 19507209473948,532049001583280,14521612514267224,396222067735245796,

%U 10812492512879834968,295042237941175359056,8051107927651445871340

%N 1/5 the number of nX3 0..4 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors

%C Column 3 of A185825

%H R. H. Hardin, <a href="/A185819/b185819.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n)=17*a(n-1)+327*a(n-2)-1020*a(n-3)-6773*a(n-4)+2794*a(n-5)+32525*a(n-6)+131655*a(n-7)-337771*a(n-8)+33788*a(n-9)+517885*a(n-10)-1145646*a(n-11)-5007180*a(n-12)+7715688*a(n-13)+39324336*a(n-14)-82942336*a(n-15)-35554304*a(n-16)+265939200*a(n-17)+170422272*a(n-18)-172261376*a(n-19)-774750208*a(n-20)-958660608*a(n-21)-1396703232*a(n-22)-1811939328*a(n-23)

%e Some solutions for 4X3 with a(1,1)=0

%e ..0..1..1....0..3..3....0..3..1....0..0..1....0..2..3....0..0..2....0..0..2

%e ..0..1..0....0..4..3....0..3..1....0..1..1....0..2..3....0..2..2....4..4..2

%e ..0..0..0....4..4..2....0..2..2....2..1..3....0..2..4....4..4..4....1..4..4

%e ..1..1..1....4..2..2....1..1..2....2..1..3....0..2..4....1..1..1....1..1..1

%K nonn

%O 1,2

%A _R. H. Hardin_ Feb 05 2011