A185985 1/128 the number of (n+2) X 3 binary arrays with each 3 X 3 subblock trace equal to some horizontal or vertical neighbor 3 X 3 subblock trace.

0, 10, 28, 200, 876, 4838, 23840, 124114, 628932, 3229072, 16473124, 84299894, 430743744, 2202581690, 11258708588, 57560078392, 294250374492, 1504287249286, 7690165809760, 39313791606722, 200979640215060, 1027448868120896

Offset

1,2

Comments

Column 1 of A185993.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) + 7*a(n-2) - 12*a(n-3) + 27*a(n-4).

Empirical g.f.: 2*x^2*(5 - 6*x + 9*x^2) / (1 - 4*x - 7*x^2 + 12*x^3 - 27*x^4). - Colin Barker, Apr 17 2018

Example

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

Crossrefs

Cf. A185993.

Sequence in context: A332432 A219812 A345725 * A358986 A239477 A345696

Adjacent sequences: A185982 A185983 A185984 * A185986 A185987 A185988

Keyword

nonn

Author

R. H. Hardin, Feb 08 2011

Status

approved