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A231019 Number of (n+3)X(n+3) 0..3 black square subarrays x(i,j) with each element diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 4, and upper left element zero 0
6, 242, 8374, 3160834, 584293702, 1576885946694, 2042677948725090, 36336036129055657778 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Diagonal of A231023

LINKS

Table of n, a(n) for n=1..8.

EXAMPLE

Some solutions for n=2

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

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

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

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

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

CROSSREFS

Sequence in context: A080358 A233826 A156936 * A254009 A072228 A229631

Adjacent sequences:  A231016 A231017 A231018 * A231020 A231021 A231022

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 03 2013

STATUS

approved

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Last modified May 23 11:20 EDT 2019. Contains 323514 sequences. (Running on oeis4.)