A269203 Number of 3 X n 0..3 arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling three no more than once.

64, 1740, 25572, 400428, 5877228, 84310620, 1184381844, 16385570076, 223935582828, 3030348558252, 40673437553748, 542180347359564, 7185077761974828, 94737850175764476, 1243661129422894356, 16262904060512571516, 211935250795961093868, 2753454797480878594380

Offset

1,1

Links

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

Formula

Empirical: a(n) = 24*a(n-1) -130*a(n-2) -248*a(n-3) +935*a(n-4) +272*a(n-5) -1768*a(n-6) +960*a(n-7) -144*a(n-8).

Example

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

Crossrefs

Row 3 of A269201.

Sequence in context: A269660 A234240 A017115 * A005609 A065788 A264275

Adjacent sequences: A269200 A269201 A269202 * A269204 A269205 A269206

Keyword

nonn

Author

R. H. Hardin, Feb 20 2016

Status

approved