A208807 Number of n-bead necklaces labeled with numbers -1..1 not allowing reversal, with sum zero and three times sum of squares <= n*(1)*(1+1).

1, 1, 3, 4, 5, 22, 37, 62, 281, 558, 1031, 4700, 9913, 19766, 87719, 193172, 403805, 1757552, 3983935, 8629150, 36900723, 85538100, 190374581, 801821488, 1891960745, 4303219652, 17883751583, 42817714086, 99138620363, 407163066510

Offset

1,3

Comments

Column 1 of A208814.

Links

R. H. Hardin, Table of n, a(n) for n = 1..31

Example

Some solutions for n=6:
.-1...-1...-1...-1...-1...-1...-1....0...-1...-1...-1...-1...-1...-1...-1...-1
..0....0...-1....0....0....1....0....0...-1....0...-1....1....0....1....0...-1
..0...-1....0....1....0...-1....0....0....0....0....0....0...-1....0...-1....1
..1....1....1...-1....1....1...-1....0....1....0....0...-1....0....0....1....1
..0....1....1....1...-1....0....1....0....0....0....1....1....1....0....0....0
..0....0....0....0....1....0....1....0....1....1....1....0....1....0....1....0

Crossrefs

Sequence in context: A039573 A037347 A116474 * A126896 A334225 A123957

Adjacent sequences: A208804 A208805 A208806 * A208808 A208809 A208810

Keyword

nonn

Author

R. H. Hardin, Mar 01 2012

Status

approved