A183359 - OEIS

%I #5 Mar 31 2012 12:35:50

%S 972,36864,34992,63504,137088,331776,829440,1806336,3852288,8294400,

%T 18137088,40144896,88897536,196448256,433465344,955551744,2106667008,

%U 4645785600,10246588416,22600912896,49849804800,109947949056

%N One quarter the number of nX7 1..4 arrays with no two neighbors of any element equal to each other

%C Column 7 of A183362

%H R. H. Hardin, <a href="/A183359/b183359.txt">Table of n, a(n) for n = 1..58</a>

%F Empirical: a(n)=2*a(n-1)+a(n-3)-2*a(n-4)+4*a(n-5)+a(n-6)-a(n-9) for n>14

%e Some solutions for 5X7 with a(1,1)=1

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Jan 04 2011