A188353 Number of arrangements of n+1 numbers x(i) in -4..4 with the sum of x(i)*x(i+1) equal to zero.

17, 153, 497, 4201, 22229, 181449, 1264985, 10396729, 81850801, 684867741, 5680170701, 48268778269, 410276328441, 3525682027185, 30364372592101, 262996695840081, 2283098828435689, 19886474577091625, 173553193860930897

Offset: 1

Author

R. H. Hardin Mar 28 2011

Keywords

• nonn

Comments

Column 4 of A188358

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..60