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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A209338 Number of n-bead necklaces labeled with numbers -2..2 allowing reversal, with sum zero with no three beads in a row equal. 0
1, 3, 4, 15, 40, 146, 514, 2032, 8076, 33310, 138966, 589618, 2525494, 10923868, 47599638, 208824200, 921391230, 4086463748, 18206487792 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 2 of A209344.

LINKS

Table of n, a(n) for n=1..19.

EXAMPLE

Some solutions for n=10:

.-2...-2...-2...-2...-2...-2...-2...-2...-2...-2...-2...-2...-2...-2...-2...-2

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

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

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

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

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

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

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

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

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

CROSSREFS

Sequence in context: A041665 A052133 A209479 * A127144 A042771 A176755

Adjacent sequences:  A209335 A209336 A209337 * A209339 A209340 A209341

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 06 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 November 18 04:44 EST 2019. Contains 329248 sequences. (Running on oeis4.)