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A201840 Number of zero-sum nX1 -1..1 arrays with every element equal to at least one horizontal or vertical neighbor 1
0, 1, 1, 3, 1, 9, 7, 25, 25, 83, 85, 277, 327, 965, 1267, 3479, 4933, 12713, 19267, 47079, 75269, 176317, 294185, 665893, 1149735, 2531711, 4492395, 9677791, 17552673, 37160277, 68590367, 143219187, 268096983, 553710855, 1048276003, 2146430287 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Column 1 of A201847

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

EXAMPLE

Some solutions for n=9

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

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

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

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

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

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

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

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

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

CROSSREFS

Sequence in context: A210395 A019770 A136320 * A088640 A114195 A185948

Adjacent sequences:  A201837 A201838 A201839 * A201841 A201842 A201843

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 06 2011

STATUS

approved

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Last modified June 6 04:15 EDT 2020. Contains 334859 sequences. (Running on oeis4.)