A222016 Number of nX3 arrays of occupancy after each element stays put or moves to some horizontal or vertical neighbor, without move-in move-out straight through or left turns

6, 188, 3875, 86088, 1892859, 41636522, 916164266, 20156123913, 443464985963, 9756801621038, 214662580479904, 4722860659023550, 103909179716386461, 2286139384890550049, 50298089904801491960, 1106624498857041822230

Offset

1,1

Comments

Column 3 of A222020

Links

R. H. Hardin, Table of n, a(n) for n = 1..195

Formula

Empirical: a(n) = 6*a(n-1) +286*a(n-2) +1731*a(n-3) -3366*a(n-4) -58755*a(n-5) -73158*a(n-6) +744580*a(n-7) +1606773*a(n-8) -5847271*a(n-9) -13299665*a(n-10) +35585397*a(n-11) +56858689*a(n-12) -168213873*a(n-13) -99886051*a(n-14) +532060381*a(n-15) -127805646*a(n-16) -951724652*a(n-17) +874261131*a(n-18) +729065885*a(n-19) -1511277493*a(n-20) +275583551*a(n-21) +992093720*a(n-22) -708567632*a(n-23) -119679569*a(n-24) +310913349*a(n-25) -92576435*a(n-26) -25624476*a(n-27) +17876348*a(n-28) -1254086*a(n-29) -1085212*a(n-30) +391330*a(n-31) -46391*a(n-32) -25190*a(n-33) +7306*a(n-34) +873*a(n-35) -236*a(n-36) -12*a(n-37)

Example

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

Crossrefs

Sequence in context: A015004 A324094 A129046 * A059491 A024279 A350873

Adjacent sequences: A222013 A222014 A222015 * A222017 A222018 A222019

Keyword

nonn

Author

R. H. Hardin Feb 05 2013

Status

approved