login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A211043 1/3 the number of n X n 0..2 symmetric matrices with every element equal to one, two or three horizontal and vertical neighbors. 0
0, 1, 8, 156, 7480, 898680, 266674964, 196750879896, 360466213243792, 1640421325318165822, 18541481770815952051304, 520535380394250894532873968, 36296751650483051319011293939152 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..13.

EXAMPLE

Some solutions for n=4

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

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

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

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

CROSSREFS

Sequence in context: A251586 A221098 A171211 * A025605 A114223 A278669

Adjacent sequences:  A211040 A211041 A211042 * A211044 A211045 A211046

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 30 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 28 08:00 EDT 2022. Contains 357063 sequences. (Running on oeis4.)