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A202047 T(n,k)=Number of zero-sum nXk -1..1 arrays with every element unequal to at most two horizontal and vertical neighbors 8
1, 3, 3, 7, 19, 7, 19, 73, 73, 19, 51, 335, 415, 335, 51, 141, 1593, 2921, 2921, 1593, 141, 393, 7669, 19541, 31753, 19541, 7669, 393, 1107, 37311, 149149, 359017, 359017, 149149, 37311, 1107, 3139, 184335, 1067983, 4188917, 6221993, 4188917, 1067983 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Table starts

....1.......3.........7.........19..........51..........141..........393

....3......19........73........335........1593.........7669........37311

....7......73.......415.......2921.......19541.......149149......1067983

...19.....335......2921......31753......359017......4188917.....49553277

...51....1593.....19541.....359017.....6221993....119412837...2229078023

..141....7669....149149....4188917...119412837...3573771563.108356007319

..393...37311...1067983...49553277..2229078023.108356007319

.1107..184335...8193025..594443301.43322352587

.3139..919889..60897081.7206865523

.8953.4620477.469758219

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..84

EXAMPLE

Some solutions for n=5 k=3

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

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

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

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

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

CROSSREFS

Column 1 is A002426

Sequence in context: A221303 A221378 A221269 * A036574 A174034 A081486

Adjacent sequences:  A202044 A202045 A202046 * A202048 A202049 A202050

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin Dec 10 2011

STATUS

approved

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Last modified April 20 14:27 EDT 2019. Contains 322310 sequences. (Running on oeis4.)