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 A186160 1/4 the number of n X n 0..3 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors 0
 0, 7, 702, 751266, 5033988714, 268995986029278 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Diagonal of A186168 LINKS Table of n, a(n) for n=1..6. EXAMPLE Some solutions for 4X4 with a(1,1)=0 ..0..2..0..2....0..0..2..0....0..2..1..1....0..0..2..2....0..2..2..1 ..0..2..0..2....0..0..2..0....0..2..0..0....0..2..1..2....0..0..0..1 ..1..2..3..3....2..3..3..3....2..1..1..0....2..2..1..0....2..3..3..1 ..1..1..1..1....2..3..2..2....2..2..1..0....3..3..3..0....2..3..0..0 CROSSREFS Sequence in context: A163016 A261696 A174855 * A129291 A229149 A159815 Adjacent sequences: A186157 A186158 A186159 * A186161 A186162 A186163 KEYWORD nonn AUTHOR R. H. Hardin Feb 13 2011 STATUS approved

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Last modified May 28 21:07 EDT 2023. Contains 363028 sequences. (Running on oeis4.)