A183914 Number of nondecreasing arrangements of n numbers in -6..6 with sum zero

1, 7, 25, 86, 252, 676, 1656, 3788, 8150, 16660, 32540, 61108, 110780, 194668, 332578, 553981, 901723, 1437269, 2247151, 3451798, 5216252, 7764392, 11396054, 16509188, 23626234, 33427622, 46791278, 64841876, 89008530, 121095602, 163364972

Offset

1,2

Comments

Column 6 of A183917

Links

R. H. Hardin, Table of n, a(n) for n = 1..161

Formula

Empirical: a(n)=a(n-1)+2*a(n-2)-a(n-3)-a(n-4)-a(n-6)-2*a(n-7)+a(n-8)+2*a(n-9)+a(n-11)+2*a(n-12)-a(n-13)-a(n-14)+2*a(n-15)-a(n-16)-4*a(n-17)-3*a(n-20)+a(n-21)+3*a(n-22)+a(n-24)+4*a(n-25)-a(n-26)-a(n-27)+3*a(n-28)-a(n-29)-4*a(n-30)-4*a(n-33)-a(n-34)+3*a(n-35)-a(n-36)-a(n-37)+4*a(n-38)+a(n-39)+3*a(n-41)+a(n-42)-3*a(n-43)-4*a(n-46)-a(n-47)+2*a(n-48)-a(n-49)-a(n-50)+2*a(n-51)+a(n-52)+2*a(n-54)+a(n-55)-2*a(n-56)-a(n-57)-a(n-59)-a(n-60)+2*a(n-61)+a(n-62)-a(n-63)

Example

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

Crossrefs

Sequence in context: A220387 A155294 A155233 * A279216 A245769 A146933

Adjacent sequences: A183911 A183912 A183913 * A183915 A183916 A183917

Keyword

nonn

Author

R. H. Hardin Jan 07 2011

Status

approved