A183332 - OEIS

%I #7 Apr 05 2020 21:42:56

%S 3,23,66,247,899,3254,11883,43207,157266,572571,2084227,7587166,

%T 27619131,100540587,365994058,1332312171,4849957923,17655092138,

%U 64269069107,233955917683,851659617442,3100259701471,11285741436475,41082996924906

%N Number of n X 4 binary arrays with each 1 adjacent to exactly two 0's.

%C Column 4 of A183335.

%H R. H. Hardin, <a href="/A183332/b183332.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n)=2*a(n-1)+2*a(n-2)+9*a(n-3)+14*a(n-4)+20*a(n-5)+9*a(n-6)-4*a(n-7)-24*a(n-8)-46*a(n-9)-43*a(n-10)-35*a(n-11)-16*a(n-12)+6*a(n-13)+11*a(n-14)+8*a(n-15)+7*a(n-16)+2*a(n-17)+a(n-18)+2*a(n-19).

%e Some solutions for 8 X 4

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

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

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

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Jan 03 2011