A280438 Number of n X 6 0..1 arrays with no element equal to more than one of its horizontal and vertical neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.

10, 68, 136, 232, 360, 548, 834, 1284, 2008, 3188, 5128, 8332, 13638, 22436, 37032, 61248, 101416, 168020, 278410, 461284, 764088, 1265228, 2094216, 3464892, 5730190, 9472388, 15651784, 25851544, 42680808, 70438148, 116203218, 191632452

Offset

1,1

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>7.

Empirical g.f.: 2*x*(5 + 14*x - 48*x^2 - 10*x^3 + 36*x^4 + 18*x^5 + 6*x^6) / ((1 - x)^2*(1 - x - x^2)^2). - Colin Barker, Feb 13 2019

Example

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

Crossrefs

Column 6 of A280440.

Sequence in context: A197783 A197751 A144052 * A192021 A026984 A104598

Adjacent sequences: A280435 A280436 A280437 * A280439 A280440 A280441

Keyword

nonn

Author

R. H. Hardin, Jan 03 2017

Status

approved