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A187630 Number of (n+1)X(n+1) 0..2 arrays with the array of 2X2 subblock determinants antisymmetric under horizontal and vertical reflection and each non-centerline 2X2 subblock nonsingular 0
31, 446, 1648, 557382, 672698, 21411605018, 22329564088 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A187633

LINKS

Table of n, a(n) for n=1..7.

EXAMPLE

Some solutions for 4X4

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

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

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

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

CROSSREFS

Sequence in context: A332909 A084234 A187622 * A118196 A160443 A125466

Adjacent sequences:  A187627 A187628 A187629 * A187631 A187632 A187633

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 12 2011

STATUS

approved

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Last modified September 23 05:28 EDT 2021. Contains 347609 sequences. (Running on oeis4.)