A199526 Number of -4..4 arrays x(0..n-1) of n elements with zero sum and no two consecutive zero elements.

1, 8, 60, 464, 3734, 30484, 252154, 2105064, 17701326, 149708146, 1272108368, 10851700690, 92875809416, 797134845184, 6858361265978, 59133629878796, 510815878314050, 4419961056157870, 38301854208088068, 332355738077962284

Offset: 1

Author

R. H. Hardin, Nov 07 2011

Keywords

• nonn

Comments

Column 4 of A199530.

Examples

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

Links

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

Crossrefs

Cf. A199530.