A297396 Number of 3 X n 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1 neighboring 1.

1, 9, 19, 37, 127, 323, 763, 2121, 5557, 14031, 37065, 97027, 250371, 653707, 1706245, 4431885, 11544027, 30085525, 78290135, 203852347, 530958219, 1382353401, 3599332477, 9373032927, 24405570561, 63547912011, 165475162027, 430875964651

Offset

1,2

Links

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

Formula

Empirical: a(n) = a(n-1) + a(n-2) + 8*a(n-3) + a(n-4) - 2*a(n-6).

Empirical g.f.: x*(1 + 8*x + 9*x^2 + x^3 - 2*x^4 - 2*x^5) / (1 - x - x^2 - 8*x^3 - x^4 + 2*x^6). - Colin Barker, Feb 28 2019

Example

Some solutions for n=5:
..0..0..0..1..1. .0..1..1..0..0. .0..0..0..1..0. .1..0..0..0..0
..1..1..0..0..0. .0..0..0..0..0. .0..0..0..0..1. .0..1..0..0..0
..0..0..0..1..1. .0..0..0..1..1. .0..0..0..0..0. .0..0..0..1..1

Crossrefs

Row 3 of A297395.

Sequence in context: A195042 A157034 A198590 * A145958 A290245 A039299

Adjacent sequences: A297393 A297394 A297395 * A297397 A297398 A297399

Keyword

nonn

Author

R. H. Hardin, Dec 29 2017

Status

approved