A186788 Half the number of (n+2) X 3 binary arrays with each 3 X 3 subblock having a sum in 2..7.

246, 1910, 14825, 115069, 893145, 6932452, 53808589, 417653681, 3241761282, 25162034228, 195303697871, 1515916163938, 11766299569341, 91328141257666, 708874471232044, 5502170623914248, 42706971125717460, 331484700748035803

Offset

1,1

Comments

Column 1 of A186796.

Links

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

Formula

Empirical: a(n) = 7*a(n-1) + 4*a(n-2) + 15*a(n-3) - 9*a(n-5).

Empirical g.f.: x*(246 + 188*x + 471*x^2 - 36*x^3 - 288*x^4) / (1 - 7*x - 4*x^2 - 15*x^3 + 9*x^5). - Colin Barker, Apr 19 2018

Example

Some solutions for 4 X 3 with a(1,1)=0:
..0..0..1....0..0..0....0..1..1....0..1..1....0..0..0....0..1..0....0..1..0
..0..1..1....0..0..0....0..1..0....0..1..1....0..1..1....0..0..1....0..0..1
..0..1..0....1..1..1....0..0..1....0..1..1....0..0..1....0..1..0....1..0..0
..1..0..1....1..1..0....0..0..0....1..1..0....0..1..0....1..1..1....1..0..1

Crossrefs

Cf. A186796.

Sequence in context: A067916 A229577 A186796 * A074995 A251524 A251517

Adjacent sequences: A186785 A186786 A186787 * A186789 A186790 A186791

Keyword

nonn

Author

R. H. Hardin, Feb 26 2011

Status

approved