A188246 Number of arrangements of n+2 nonzero numbers x(i) in -6..6 with the sum of x(i)*x(i+1) equal to zero

144, 436, 6376, 43440, 521124, 4875112, 55994544, 591604824, 6764014136, 75116513672, 862566555260, 9803647311540, 113184217957288, 1302374837233636, 15107289166289400, 175125528108662876, 2039302796727309112

Offset

1,1

Comments

Column 6 of A188249

Links

R. H. Hardin, Table of n, a(n) for n = 1..26

Example

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

Crossrefs

Sequence in context: A248551 A178972 A250787 * A258382 A151820 A322905

Adjacent sequences: A188243 A188244 A188245 * A188247 A188248 A188249

Keyword

nonn

Author

R. H. Hardin Mar 25 2011

Status

approved