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A202040 Number of zero-sum n X n -1..1 arrays with every element unequal to at most two horizontal and vertical neighbors 0
1, 19, 415, 31753, 6221993, 3573771563 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Diagonal of A202047

LINKS

Table of n, a(n) for n=1..6.

EXAMPLE

Some solutions for n=4

.-1.-1..0.-1...-1..1..1.-1....0..0..0..1...-1..0..0..1...-1.-1..0.-1

..1..0..0..0...-1.-1.-1.-1....1..0..0..1....0..0..0.-1....1..1..0..0

..1..0..0..0....1..1..1..1....1.-1.-1..1....1..1..0.-1....1..1..1..1

..0..1..1.-1....1..0..0.-1....0.-1.-1.-1....0..1..0.-1...-1.-1.-1..0

CROSSREFS

Sequence in context: A252927 A172740 A172816 * A244765 A069612 A077716

Adjacent sequences:  A202037 A202038 A202039 * A202041 A202042 A202043

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 10 2011

STATUS

approved

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Last modified October 7 14:13 EDT 2022. Contains 357271 sequences. (Running on oeis4.)