The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
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!)
A209005 Number of n-bead necklaces labeled with numbers -6..6 not allowing reversal, with sum zero and first and second differences in -6..6. 0
1, 2, 7, 26, 137, 923, 6261, 43228, 293991, 1993292, 13620471, 94043892, 656241875 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Column 6 of A209007.
LINKS
Table of n, a(n) for n=1..13.
EXAMPLE
Some solutions for n=6:
.-2...-5...-1...-4...-4...-5...-4...-1...-5...-2...-2...-2...-4...-5...-3...-1
..1...-5...-1...-4...-1...-1...-3...-1...-3...-2....1....0...-4...-4...-1....0
..0....1....1...-2....1....4....3....0....1...-1....0....1....2....0...-1....0
..1....5...-1....4....2....5....3....1....5...-1....1....2....2....4....1...-1
..0....4....1....4....3....0....2....1....4....3...-1....0....2....5....3....2
..0....0....1....2...-1...-3...-1....0...-2....3....1...-1....2....0....1....0
CROSSREFS
Sequence in context: A358493 A341900 A300049 * A361242 A068870 A345682
Adjacent sequences: A209002 A209003 A209004 * A209006 A209007 A209008
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 04 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 May 13 02:15 EDT 2024. Contains 372497 sequences. (Running on oeis4.)