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!)
A208798 Number of n-bead necklaces labeled with numbers -1..1 allowing reversal, with sum zero and three times sum of squares <= n*(1)*(1+1). 1
1, 1, 2, 3, 3, 15, 22, 38, 147, 296, 526, 2421, 5017, 10025, 43986, 96951, 202141, 880269, 1993222, 4317765, 18453137, 42777491, 95192956, 400944526, 946008489, 2151685046, 8941940220, 21409059701, 49569448411, 203582329338, 493419056384, 1159647133954 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Andrew Howroyd, Table of n, a(n) for n = 1..100

EXAMPLE

All solutions for n=6:

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

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

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

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

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

..1....0....1....0....1....1....1....1....1....0....1....0....0....1....1

CROSSREFS

Column 1 of A208805.

Sequence in context: A109203 A039792 A076358 * A090522 A114728 A057676

Adjacent sequences:  A208795 A208796 A208797 * A208799 A208800 A208801

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 01 2012

EXTENSIONS

a(29)-a(32) from Andrew Howroyd, Mar 02 2017

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 29 01:05 EDT 2022. Contains 357082 sequences. (Running on oeis4.)