A232509 - OEIS

A232509

Number of (n+1)X(2+1) 0..2 arrays with every element next to itself plus and minus one within the range 0..2 horizontally, diagonally or antidiagonally, with no adjacent elements equal.

16, 52, 200, 784, 3052, 11900, 46432, 181184, 707044, 2759212, 10767816, 42021520, 163989692, 639972924, 2497507216, 9746573088, 38036202612, 148437067820, 579278732344, 2260647259184, 8822222791628, 34428907339516, 134359524664384

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Column 2 of A232515

LINKS

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

FORMULA

Empirical: a(n) = 4*a(n-1) +a(n-2) -4*a(n-3) -5*a(n-4) -2*a(n-5) +a(n-6) +2*a(n-7).

Empirical: G.f.: -4*x*(4-3*x-6*x^2-x^3+x^4+x^6) / ( -1+4*x+x^2-4*x^3-5*x^4-2*x^5+x^6+2*x^7 ). - R. J. Mathar, Nov 23 2014

EXAMPLE

Some solutions for n=7

..2..1..2....0..1..2....2..1..0....0..1..0....0..1..0....2..1..2....2..1..2

..2..1..0....2..1..0....2..1..0....2..1..0....2..1..2....0..1..2....0..1..0

..2..1..0....0..1..2....0..1..0....0..1..2....2..1..0....0..1..0....0..1..2

..2..1..0....0..1..2....2..1..0....2..1..0....2..1..0....2..1..0....0..1..0

..0..1..0....2..1..2....2..1..0....0..1..0....2..1..2....0..1..2....0..1..2

..0..1..2....2..1..0....0..1..0....2..1..0....2..1..2....0..1..2....2..1..0

..0..1..0....0..1..2....0..1..2....2..1..0....2..1..0....2..1..2....2..1..0

..0..1..2....2..1..2....0..1..2....2..1..2....2..1..0....0..1..2....2..1..2

CROSSREFS

Sequence in context: A354886 A087701 A211586 * A087973 A351584 A332591

Adjacent sequences: A232506 A232507 A232508 * A232510 A232511 A232512

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 25 2013

STATUS

approved