A186932 Number of (n+1) X 3 binary arrays with every 2 X 2 subblock trace equal to exactly one or two horizontal and vertical neighbor 2 X 2 subblock traces.

24, 104, 472, 1664, 6848, 27272, 108128, 431656, 1719312, 6845968, 27282352, 108671048, 432902384, 1724605424, 6870205712, 27368517688, 109028322640, 434332786176, 1730241699608, 6892737739416, 27458456022120, 109385692125040

Offset

1,1

Comments

Column 2 of A186939.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n)=2*a(n-1)+4*a(n-2)+12*a(n-3)+4*a(n-4)+17*a(n-5)+136*a(n-6)-78*a(n-7)-269*a(n-8)-496*a(n-9)+226*a(n-10)+441*a(n-11)-110*a(n-12)+372*a(n-13)+448*a(n-15)-512*a(n-16).

Example

Some solutions for 4 X 3
..0..0..0....0..0..0....1..1..0....1..0..1....0..1..0....1..0..0....0..1..1
..0..1..1....1..0..0....1..1..1....0..0..1....1..1..0....0..0..1....1..1..0
..1..1..0....1..1..1....1..1..0....0..0..0....0..0..0....0..0..0....1..1..1
..1..1..1....0..1..0....0..1..0....0..1..1....1..0..0....1..1..1....1..0..0

Crossrefs

Cf. A186939.

Sequence in context: A100155 A304415 A268804 * A275506 A185743 A027265

Adjacent sequences: A186929 A186930 A186931 * A186933 A186934 A186935

Keyword

nonn

Author

R. H. Hardin, Mar 01 2011

Status

approved