A188357 Number of arrangements of n+1 numbers x(i) in -8..8 with the sum of x(i)*x(i+1) equal to zero.

33, 561, 2161, 34625, 283893, 4409889, 55520361, 870473329, 12869671489, 204942934341, 3212586862645

Offset: 1

Author

R. H. Hardin Mar 28 2011

Keywords

• nonn

Comments

Column 8 of A188358

Examples

			Some solutions for n=4
.-7....6...-2...-3....4...-7...-5....0....0....0...-4...-7....8....1...-5....3
.-1....5....0....8....3....0....0...-6....0...-4...-2...-7...-6...-8....0....3
..7...-6...-7....3....0...-3...-6...-4...-3....3....4....5....0....1...-7...-5
.-2....4...-5...-7....4....0....4....3...-7...-4....0...-7....6...-8....5...-3
.-7....6....7...-3...-3...-2....6...-4....3...-6...-3...-3....8...-3....7....3