A188558 Number of 7 X n binary arrays without the pattern 0 1 diagonally, vertically, antidiagonally or horizontally.

8, 15, 28, 52, 96, 176, 320, 576, 1024, 1793, 3084, 5200, 8584, 13866, 21920, 33932, 51480, 76627, 112028, 161052, 227920, 317860, 437280, 593960, 797264, 1058373, 1390540, 1809368, 2333112, 2983006, 3783616, 4763220, 5954216, 7393559, 9123228

Offset

1,1

Comments

Row 7 of A188553.

Links

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

Formula

Empirical: a(n) = (1/5040)*n^7 - (1/360)*n^6 + (11/360)*n^5 - (1/9)*n^4 + (427/720)*n^3 + (41/360)*n^2 + (709/210)*n + 4.

Conjectures from Colin Barker, Apr 28 2018: (Start)

G.f.: x*(8 - 49*x + 132*x^2 - 200*x^3 + 184*x^4 - 102*x^5 + 32*x^6 - 4*x^7) / (1 - x)^8.

a(n) = 8*a(n-1) - 28*a(n-2) + 56*a(n-3) - 70*a(n-4) + 56*a(n-5) - 28*a(n-6) + 8*a(n-7) - a(n-8) for n>8.

(End)

Example

Some solutions for 7 X 3:
..1..1..1....1..1..1....1..1..1....1..1..1....1..1..1....1..1..1....1..1..1
..1..1..1....1..1..1....1..1..1....1..1..1....1..1..1....1..1..1....1..1..1
..1..1..1....1..1..0....1..1..1....1..1..1....1..1..1....1..1..1....1..1..1
..1..1..1....1..0..0....1..1..1....1..1..1....1..1..0....1..1..1....1..1..1
..1..1..1....0..0..0....1..1..0....1..1..1....0..0..0....1..1..1....1..1..1
..1..1..1....0..0..0....1..0..0....1..0..0....0..0..0....1..1..1....1..1..0
..0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....1..0..0....1..0..0

Crossrefs

Cf. A188553.

Sequence in context: A318111 A240522 A132298 * A123526 A083686 A293360

Adjacent sequences: A188555 A188556 A188557 * A188559 A188560 A188561

Keyword

nonn

Author

R. H. Hardin, Apr 04 2011

Status

approved