A221251 Number of nX4 arrays of occupancy after each element moves to some horizontal or antidiagonal neighbor, with no occupancy greater than 2

4, 81, 2116, 58081, 1612900, 44903401, 1250753956, 34842328921, 970622980804, 27039303204489, 753252725702500, 20983889126032561, 584562920742585316, 16284579460194091201, 453650957002812576484, 12637673040690140943889

Offset

1,1

Comments

Column 4 of A221255

Links

R. H. Hardin, Table of n, a(n) for n = 1..23

Formula

Empirical: a(n) = 39*a(n-1) -356*a(n-2) +1365*a(n-3) -2739*a(n-4) +2904*a(n-5) -1683*a(n-6) +573*a(n-7) -116*a(n-8) +15*a(n-9) -a(n-10)

Example

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

Crossrefs

Sequence in context: A202831 A335691 A264197 * A128911 A268206 A337155

Adjacent sequences: A221248 A221249 A221250 * A221252 A221253 A221254

Keyword

nonn

Author

R. H. Hardin Jan 06 2013

Status

approved