A183913 Number of nondecreasing arrangements of n numbers in -5..5 with sum zero.

1, 6, 18, 55, 141, 338, 734, 1514, 2934, 5448, 9686, 16660, 27718, 44916, 70922, 109583, 165821, 246448, 360002, 517971, 734517, 1028172, 1421530, 1943488, 2628824, 3521260, 4672836, 6147894, 8022362, 10388788, 13355414, 17052653

Offset: 1

Author

R. H. Hardin Jan 07 2011

Keywords

• nonn

Comments

Column 5 of A183917

Examples

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

Links

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

Formula

Empirical: a(n)=a(n-1)+2*a(n-2)-a(n-3)-a(n-4)-a(n-5)+a(n-9)-a(n-10)+3*a(n-12)+a(n-13)-a(n-14)-a(n-16)-2*a(n-17)-a(n-18)-a(n-20)+a(n-22)+2*a(n-23)+2*a(n-24)+a(n-25)-a(n-27)-a(n-29)-2*a(n-30)-a(n-31)-a(n-33)+a(n-34)+3*a(n-35)-a(n-37)+a(n-38)-a(n-42)-a(n-43)-a(n-44)+2*a(n-45)+a(n-46)-a(n-47)