A201989 T(n,k) is the number of n X k zero-sum -3..3 arrays with rows and columns lexicographically nondecreasing.

1, 4, 4, 8, 77, 8, 18, 1170, 1170, 18, 32, 14107, 134217, 14107, 32, 58, 139471, 11648559, 11648559, 139471, 58, 94, 1177568, 803133854, 7375608084, 803133854, 1177568, 94, 151, 8721417, 46034224561, 3674187761233, 3674187761233

Offset: 1

Author

R. H. Hardin, Dec 07 2011

Keywords

• nonn
• tabl

Examples

			Table starts:
...1........4..............8.................18...................32
...4.......77...........1170..............14107...............139471
...8.....1170.........134217...........11648559............803133854
..18....14107.......11648559.........7375608084........3674187761233
..32...139471......803133854......3674187761233....13189629907532856
..58..1177568....46034224561...1507315600099908.38785259210265819578
..94..8721417..2263314310579.526500713340421071
.151.57801225.97590406110264
Some solutions for n=3 and k=3:
.-3..2..2...-3.-1..3...-3.-3..2...-3.-1..1...-2..0..2...-3.-1..1...-3.-3.-3
..1.-2.-1...-3..1.-2...-1..0..1....0.-3..2...-2..3.-1....1..2.-3....1..2..3
..3.-2..0....0..2..3....0..1..3....2..2..0...-1.-1..2....3..2.-2....2.-1..2
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..59

Crossrefs

Column 1 is A001977.