A208802 Number of n-bead necklaces labeled with numbers -5..5 allowing reversal, with sum zero and three times sum of squares <= n*(5)*(5+1).

1, 4, 12, 84, 561, 4566, 38668, 347219, 3174337, 29584366, 281335070, 2698884632, 26233302819, 257404858844, 2542798716528, 25321003256022, 253598478348859, 2553267620742628, 25839412648600258, 262578227718642301

Offset

1,2

Links

Andrew Howroyd, Table of n, a(n) for n = 1..50

Example

Some solutions for n=6:
.-3...-4...-3...-4...-4...-4...-4...-3...-4...-3...-3...-3...-5...-3...-5...-5
..0...-2...-1....1...-3...-1...-1....0...-1...-1...-1...-1...-2...-1...-1...-2
.-3....3....1...-2....1....3...-1...-1....2....5....2....3....0....5....2....1
..1....4...-1....3....2...-3....5....0...-2....1....4....0....4...-2...-1...-1
..1...-2....1....1...-1....2....0....4....3...-2...-2...-2....0...-1....1....3
..4....1....3....1....5....3....1....0....2....0....0....3....3....2....4....4

Crossrefs

Column 5 of A208805.

Sequence in context: A205337 A359047 A263866 * A226960 A081214 A331087

Adjacent sequences: A208799 A208800 A208801 * A208803 A208804 A208805

Keyword

nonn

Author

R. H. Hardin, Mar 01 2012

Extensions

a(13)-a(20) from Andrew Howroyd, Mar 02 2017

Status

approved