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A187631 Number of (n+1)X(n+1) 0..3 arrays with the array of 2X2 subblock determinants antisymmetric under horizontal and vertical reflection and each non-centerline 2X2 subblock nonsingular 0
64, 2924, 14044, 31903442, 33869160 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A187633

LINKS

Table of n, a(n) for n=1..5.

EXAMPLE

Some solutions for 4X4

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

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

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

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

CROSSREFS

Sequence in context: A283128 A295714 A187623 * A221831 A282397 A297100

Adjacent sequences:  A187628 A187629 A187630 * A187632 A187633 A187634

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 12 2011

STATUS

approved

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Last modified September 16 21:28 EDT 2021. Contains 347473 sequences. (Running on oeis4.)