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A187459 Number of (n+1)X(n+1) 0..2 arrays with all the 2X2 subblocks nonsingular and the array of 2X2 subblock determinants symmetric 0
50, 1236, 89618, 11684688, 6112320620, 4871877392202, 17264863350746654, 83050637417670542044 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A187462

LINKS

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

EXAMPLE

Some solutions for 4X4

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

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

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

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

CROSSREFS

Sequence in context: A318760 A250520 A017766 * A035720 A161695 A162205

Adjacent sequences:  A187456 A187457 A187458 * A187460 A187461 A187462

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 10 2011

STATUS

approved

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Last modified May 28 15:04 EDT 2022. Contains 354115 sequences. (Running on oeis4.)