A188359 Number of arrangements of 4 numbers x(i) in -n..n with the sum of x(i)*x(i+1) equal to zero.

29, 117, 257, 497, 749, 1205, 1569, 2161, 2765, 3589, 4177, 5377, 6077, 7253, 8561, 10017, 10941, 12837, 13873, 16017, 17933, 19845, 21105, 24097, 25981, 28245, 30593, 33729, 35325, 39397, 41105, 44449, 47517, 50517, 53905, 59009, 61053, 64405, 68033

Offset: 1

Author

R. H. Hardin Mar 28 2011

Keywords

• nonn

Comments

Row 3 of A188358

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..135