A201887 Number of zero-sum nX4 -2..2 arrays with every element equal to at least one horizontal or vertical neighbor

5, 413, 26003, 2171313, 184247585, 16910703303, 1591685181703, 153167112074177, 14927625333671307, 1468389415886159993

Offset

1,1

Comments

Column 4 of A201888

Links

Table of n, a(n) for n=1..10.

Example

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

Crossrefs

Sequence in context: A046274 A221700 A216089 * A365370 A301309 A218406

Adjacent sequences: A201884 A201885 A201886 * A201888 A201889 A201890

Keyword

nonn

Author

R. H. Hardin Dec 06 2011

Status

approved