A202029 Number of nX4 zero-sum -1..1 arrays with rows and columns lexicographically nondecreasing

3, 56, 1341, 29363, 537572, 8249505, 108479344, 1248911674, 12812139620, 118772002152, 1006266126267, 7863720278445, 57120674129416, 388168845356086, 2481485055755353, 14994743673623870, 86001919259575522, 469898358909610160

Offset

1,1

Comments

Column 4 of A202033

Links

R. H. Hardin, Table of n, a(n) for n = 1..111

Example

Some solutions for n=4
.-1.-1.-1..1...-1.-1.-1..0...-1..0..0..1...-1..0..0..1...-1.-1.-1..0
.-1..0..1.-1....0..1..1.-1....0.-1..0.-1....0..0..0..1...-1..1..1..1
..1..1.-1..0....1.-1..0..0....1..1..0.-1....0..0..1.-1....0.-1..1.-1
..1..1..0..0....1..0..0..1....1..1..0.-1....1.-1.-1..0....0..1..1..0

Crossrefs

Sequence in context: A263886 A160876 A241136 * A287396 A335804 A070731

Adjacent sequences: A202026 A202027 A202028 * A202030 A202031 A202032

Keyword

nonn

Author

R. H. Hardin Dec 09 2011

Status

approved