A188748 Number of 3 X n binary arrays without the pattern 1 1 1 diagonally, vertically or antidiagonally.

7, 49, 292, 1723, 10327, 61996, 371641, 2227333, 13350748, 80027347, 479695855, 2875358812, 17235289777, 103310698477, 619258487404, 3711920099323, 22249757087527, 133368089673676, 799426585401961, 4791872379016597

Offset

1,1

Comments

Row 3 of A188747.

Links

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

Formula

Empirical: a(n) = 6*a(n-1) -2*a(n-2) +11*a(n-3) +10*a(n-4) -30*a(n-5) -12*a(n-6).

Empirical g.f.: x*(7 + 7*x + 12*x^2 - 8*x^3 - 36*x^4 - 12*x^5) / (1 - 6*x + 2*x^2 - 11*x^3 - 10*x^4 + 30*x^5 + 12*x^6). - Colin Barker, Feb 20 2018

Example

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

Crossrefs

Sequence in context: A218266 A213295 A189258 * A188986 A146884 A113235

Adjacent sequences: A188745 A188746 A188747 * A188749 A188750 A188751

Keyword

nonn

Author

R. H. Hardin, Apr 09 2011

Status

approved