A202004 Number of -6..6 circular arrays x(0..n+1) of n+2 elements with zero sums of x(i) and x(i)*x((i+1) mod (n+2))

1, 169, 231, 4327, 33699, 511257, 4460689, 48525711, 529141383, 6524977447, 74784050095, 908188232827, 10930623434631, 133367299797625, 1609848080492237, 19647665104267177, 240376888100965909

Offset

1,2

Comments

Column 6 of A202006

Links

R. H. Hardin, Table of n, a(n) for n = 1..32

Example

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

Crossrefs

Sequence in context: A350381 A018820 A231632 * A020249 A287391 A325421

Adjacent sequences: A202001 A202002 A202003 * A202005 A202006 A202007

Keyword

nonn

Author

R. H. Hardin Dec 07 2011

Status

approved