A280669 Number of n X 4 0..2 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors and with new values introduced in order 0 sequentially upwards.

11, 338, 10205, 310365, 9439606, 287101721, 8732086113, 265582964074, 8077601392565, 245677069239189, 7472171430204190, 227263155064756577, 6912119473224669225, 210229395075140809474, 6394044362928373953677

Offset

1,1

Links

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

Formula

Empirical: a(n) = 29*a(n-1) + 44*a(n-2) - 27*a(n-3) - 81*a(n-4) for n>5.

Empirical g.f.: x*(11 + 19*x - 81*x^2 - 155*x^3 + 18*x^4) / (1 - 29*x - 44*x^2 + 27*x^3 + 81*x^4). - Colin Barker, Feb 14 2019

Example

Some solutions for n=3:
..0..1..0..2. .0..0..1..1. .0..0..1..1. .0..1..2..2. .0..1..2..0
..1..2..0..2. .2..0..2..1. .2..2..0..2. .2..0..0..2. .1..0..2..1
..1..0..1..1. .1..0..0..1. .0..1..0..0. .1..1..0..2. .0..1..2..2

Crossrefs

Column 4 of A280673.

Sequence in context: A106717 A215015 A219072 * A195505 A092609 A091537

Adjacent sequences: A280666 A280667 A280668 * A280670 A280671 A280672

Keyword

nonn

Author

R. H. Hardin, Jan 07 2017

Status

approved