A199851 Number of -n..n arrays x(0..6) of 7 elements with zero sum and no element more than one greater than the previous.

153, 575, 1393, 2958, 5754, 10426, 17879, 29268, 46126, 70322, 104253, 150764, 213380, 296204, 404213, 543086, 719592, 941366, 1217343, 1557506, 1973400, 2477778, 3085247, 3811830, 4675676, 5696580, 6896795, 8300422, 9934376

Offset: 1

Author

R. H. Hardin Nov 11 2011

Keywords

• nonn

Comments

Row 7 of A199847

Examples

			Some solutions for n=6
..5....5....4....4....2....1....5....4....3....0....4....2....5....6....5....3
..4....6....3...-1....3....1....4....5....1....0....4....3....4....5....5....1
..0....2....3....0....1....2....4....3...-1....1...-2....4....4....3....4....1
..0....2...-1....0...-1....2....2...-3....0....2...-1....0....2....3...-5....1
.-2...-5....0....0....0...-2...-3...-2...-1....1....0....1...-5...-5...-4....0
.-3...-5...-5....0...-3...-1...-6...-1....0....0...-2...-5...-5...-6...-3...-3
.-4...-5...-4...-3...-2...-3...-6...-6...-2...-4...-3...-5...-5...-6...-2...-3
		

Links

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

Formula

Empirical: a(n) = 2*a(n-1) -a(n-3) -a(n-5) +a(n-6) -2*a(n-7) +2*a(n-8) +a(n-9) -a(n-13) -2*a(n-14) +2*a(n-15) -a(n-16) +a(n-17) +a(n-19) -2*a(n-21) +a(n-22) for n>24