A199826 Number of -2..2 arrays x(0..n+1) of n+2 elements with zero sum and no two neighbors summing to zero.

10, 40, 114, 426, 1650, 6126, 23206, 88636, 337866, 1295566, 4992364, 19269156, 74529210, 288954786, 1122363984, 4366362420, 17011617426, 66365823648, 259213619826, 1013542247970, 3966939195402, 15540399135516, 60929935280508

Offset: 1

Author

R. H. Hardin Nov 11 2011

Keywords

• nonn

Comments

Column 2 of A199832

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..200