A188827 Number of 5 X n binary arrays without the pattern 0 1 diagonally or antidiagonally.

32, 36, 120, 400, 1360, 4624, 15776, 53824, 183744, 627264, 2141568, 7311616, 24963328, 85229824, 290992640, 993510400, 3392056320, 11581203456, 39540701184, 135000395776, 460920180736, 1573679927296, 5372879347712

Offset

1,1

Comments

Row 5 of A188824.

Links

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

Formula

Empirical: a(n) = 4*a(n-1) -8*a(n-3) +4*a(n-4) for n>5.

Empirical g.f.: 4*x*(8 - 23*x - 6*x^2 + 44*x^3 - 20*x^4) / ((1 - 4*x + 2*x^2)*(1 - 2*x^2)). - Colin Barker, Apr 30 2018

Example

Some solutions for 5 X 3:
..1..1..1....0..1..1....1..1..1....1..1..1....1..0..1....1..0..1....0..1..1
..1..1..1....1..0..1....1..1..1....1..1..1....0..0..0....0..1..0....1..0..1
..1..1..1....0..1..0....1..1..1....1..1..1....0..0..0....1..0..1....0..0..0
..1..0..0....1..0..0....1..0..1....1..0..1....0..0..0....0..1..0....0..0..0
..0..0..0....0..0..0....0..1..0....0..0..0....0..0..0....1..0..0....0..0..0

Crossrefs

Cf. A188824.

Sequence in context: A335103 A045226 A258699 * A030094 A082591 A070624

Adjacent sequences: A188824 A188825 A188826 * A188828 A188829 A188830

Keyword

nonn

Author

R. H. Hardin, Apr 11 2011

Status

approved