A281209 Number of 5 X n 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.

0, 130, 448, 676, 1141, 1906, 3137, 5160, 8510, 14084, 23379, 38894, 64795, 108022, 180126, 300318, 500525, 833770, 1388053, 2309332, 3839550, 6379528, 10592935, 17578086, 29151695, 48317346, 80038622, 132514530, 219282785, 362687074

Offset

1,2

Links

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

Formula

Empirical: a(n) = 4*a(n-1) - 4*a(n-2) - 2*a(n-3) + 4*a(n-4) - a(n-6) for n>11.

Empirical g.f.: x^2*(130 - 72*x - 596*x^2 + 489*x^3 + 422*x^4 - 363*x^5 - 56*x^6 + 114*x^7 + 10*x^8 - 4*x^9) / ((1 - x)^2*(1 - x - x^2)^2). - Colin Barker, Feb 18 2019

Example

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

Crossrefs

Row 5 of A281205.

Sequence in context: A252082 A253044 A253037 * A253036 A187723 A278658

Adjacent sequences: A281206 A281207 A281208 * A281210 A281211 A281212

Keyword

nonn

Author

R. H. Hardin, Jan 17 2017

Status

approved