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 A230657 Number of n X n 0..2 black square subarrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value 2-x(i,j) 0
 1, 3, 15, 123, 8613, 337977, 169006665, 40860127671, 131515599970167, 201844710508818147, 4141132208926170478473, 40464088148356899296269059 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Diagonal of A230661 LINKS Table of n, a(n) for n=1..12. EXAMPLE Some solutions for n=5 ..x..1..x..1..x....x..2..x..0..x....x..1..x..1..x....x..1..x..1..x ..1..x..1..x..1....0..x..1..x..2....1..x..0..x..1....1..x..2..x..1 ..x..2..x..2..x....x..1..x..0..x....x..2..x..1..x....x..0..x..0..x ..0..x..1..x..0....2..x..2..x..1....2..x..1..x..2....2..x..0..x..2 ..x..2..x..1..x....x..0..x..1..x....x..0..x..0..x....x..2..x..0..x CROSSREFS Sequence in context: A191371 A113077 A251661 * A246573 A270503 A212553 Adjacent sequences: A230654 A230655 A230656 * A230658 A230659 A230660 KEYWORD nonn AUTHOR R. H. Hardin, Oct 27 2013 STATUS approved

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Last modified June 22 04:48 EDT 2024. Contains 373565 sequences. (Running on oeis4.)