A186168 - OEIS

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A186168

T(n,k)=1/4 the number of nXk 0..3 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors

0, 1, 1, 1, 7, 1, 4, 48, 48, 4, 7, 321, 702, 321, 7, 19, 2175, 14364, 14364, 2175, 19, 40, 14748, 253341, 751266, 253341, 14748, 40, 97, 99933, 4762206, 37402872, 37402872, 4762206, 99933, 97, 217, 677283, 87054174, 1899336597, 5033988714, 1899336597

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

1,5

COMMENTS

Table starts

...0........1............1...............4.................7.................19

...1........7...........48.............321..............2175..............14748

...1.......48..........702...........14364............253341............4762206

...4......321........14364..........751266..........37402872.........1899336597

...7.....2175.......253341........37402872........5033988714.......704281652979

..19....14748......4762206......1899336597......704281652979....268995986029278

..40....99933.....87054174.....95752776009....96951738076992.101554003879403823

..97...677283...1610684397...4840082975532.13435825601048421

.217..4590168..29645381115.244420512852030

.508.31108893.546876640548

LINKS

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

EXAMPLE

Some solutions for 5X4 with a(1,1)=0

..0..0..1..0....0..0..1..1....0..0..1..1....0..0..1..0....0..0..1..1

..0..0..1..0....0..0..3..2....0..0..2..2....0..0..1..0....0..0..2..1

..1..1..3..3....1..1..3..2....1..1..0..0....1..1..0..0....1..1..2..2

..0..0..3..3....0..1..3..2....1..3..3..0....1..1..2..1....2..2..1..0

..1..1..0..0....0..0..0..0....0..0..2..2....0..0..2..1....3..3..1..0

CROSSREFS

Column 1 is A006130(n-2)

Sequence in context: A368184 A086210 A085467 * A117182 A143301 A225459

Adjacent sequences: A186165 A186166 A186167 * A186169 A186170 A186171

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin Feb 13 2011

STATUS

approved