A207684 - OEIS

%I #5 Mar 31 2012 12:37:18

%S 9,81,166,436,964,2132,4846,11301,25496,57407,131250,299913,680860,

%T 1542076,3516426,8019977,18194846,41334779,94226716,214384000,

%U 486836482,1107706812,2522185912,5733889814,13035303238,29665346161,67490142684

%N Number of 4Xn 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 1 1 1 vertically

%C Row 4 of A207682

%H R. H. Hardin, <a href="/A207684/b207684.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 12*a(n-3) +12*a(n-4) +4*a(n-5) -54*a(n-6) -70*a(n-7) -34*a(n-8) +148*a(n-9) +164*a(n-10) +54*a(n-11) -237*a(n-12) -184*a(n-13) -12*a(n-14) +234*a(n-15) +87*a(n-16) -22*a(n-17) -126*a(n-18) -36*a(n-19) +19*a(n-20) +32*a(n-21) +14*a(n-22) -2*a(n-24) for n>26

%e Some solutions for n=4

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Feb 19 2012