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A201841 Number of zero-sum nX2 -1..1 arrays with every element equal to at least one horizontal or vertical neighbor 1
1, 5, 25, 97, 411, 1897, 8741, 41689, 201985, 987407, 4891069, 24457873, 123131033, 623695509, 3174983801, 16227954653, 83226630287, 428047598133, 2206766393985, 11399915802567, 58993096946055, 305739808201773, 1586610751415691 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 2 of A201847

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..95

EXAMPLE

Some solutions for n=8

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

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

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

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

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

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

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

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

CROSSREFS

Sequence in context: A223945 A197085 A273747 * A146830 A316778 A255612

Adjacent sequences:  A201838 A201839 A201840 * A201842 A201843 A201844

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 06 2011

STATUS

approved

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Last modified March 31 16:23 EDT 2020. Contains 333151 sequences. (Running on oeis4.)