login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A216986 Number of city-block distance 1, pressure limit 2 movements in an nX3 array with each element moving exactly one horizontally or vertically, no element acquiring more than two neighbors, and without 2-loops 1
0, 14, 264, 4794, 83304, 1435808, 24673352, 423651134, 7272419728, 124829530972, 2142624332680, 36776621687102, 631243274484392, 10834813398096496, 185971344332908696, 3192056733158039014, 54789226054169999632 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 3 of A216991

LINKS

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

FORMULA

Empirical: a(n) = 24*a(n-1) -121*a(n-2) +28*a(n-3) +649*a(n-4) -844*a(n-5) +175*a(n-6) +80*a(n-7) -2*a(n-8)

EXAMPLE

Some solutions for n=3 (movement: 0=n 1=e 2=s 3=w)

..1..1..2....1..2..3....1..1..2....2..3..3....1..1..2....2..3..3....1..2..2

..1..0..3....0..1..0....1..0..2....1..2..0....0..0..3....2..3..0....0..3..3

..0..3..3....0..3..0....1..0..3....0..3..3....1..0..3....1..1..0....0..1..0

CROSSREFS

Sequence in context: A304189 A115611 A205467 * A138560 A051690 A048668

Adjacent sequences:  A216983 A216984 A216985 * A216987 A216988 A216989

KEYWORD

nonn

AUTHOR

R. H. Hardin Sep 21 2012

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 22 17:25 EDT 2019. Contains 321422 sequences. (Running on oeis4.)