A207596 Number of n X 5 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 1 and 1 0 1 vertically.

15, 225, 825, 1995, 3915, 6765, 10725, 15975, 22695, 31065, 41265, 53475, 67875, 84645, 103965, 126015, 150975, 179025, 210345, 245115, 283515, 325725, 371925, 422295, 477015, 536265, 600225, 669075, 742995, 822165, 906765, 996975, 1092975

Offset

1,1

Comments

Column 5 of A207599.

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 30*n^3 + 15*n^2 - 45*n + 15.

Conjectures from Colin Barker, Jun 25 2018: (Start)

G.f.: 15*x*(1 + 11*x + x^2 - x^3) / (1 - x)^4.

a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n>4.

(End)

Example

Some solutions for n=4:
..1..1..0..0..1....0..1..1..0..1....1..0..1..1..0....0..1..1..1..1
..1..0..1..1..0....1..0..1..1..0....1..0..1..1..1....1..0..1..1..1
..0..0..1..1..0....0..0..1..1..0....0..0..1..1..1....0..0..1..1..0
..0..0..1..1..0....0..0..1..1..0....0..0..1..1..0....0..0..1..1..0

Crossrefs

Cf. A207599.

Sequence in context: A207925 A208105 A207726 * A208115 A267784 A207700

Adjacent sequences: A207593 A207594 A207595 * A207597 A207598 A207599

Keyword

nonn

Author

R. H. Hardin, Feb 19 2012

Status

approved