A201984 Number of nX2 zero-sum -3..3 arrays with rows and columns lexicographically nondecreasing

4, 77, 1170, 14107, 139471, 1177568, 8721417, 57801225, 347923603, 1924356711, 9871703167, 47329086175, 213435856527, 910247506472, 3688234465315, 14255722610693, 52746861442115, 187406263165391, 641125854338628

Offset

1,1

Comments

Column 2 of A201989

Links

R. H. Hardin, Table of n, a(n) for n = 1..177

Example

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

Crossrefs

Sequence in context: A006267 A273952 A370953 * A210519 A279437 A296997

Adjacent sequences: A201981 A201982 A201983 * A201985 A201986 A201987

Keyword

nonn

Author

R. H. Hardin Dec 07 2011

Status

approved