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A226865 Number of n X n (-1,0,1) arrays of determinants of 2X2 subblocks of some (n+1)X(n+1) binary array with rows and columns of the latter in lexicographically nondecreasing order 0
2, 13, 187, 6195, 523701, 119835087, 77611438870 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Diagonal of A226870

LINKS

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

EXAMPLE

Some solutions for n=4

..0.-1..1..0....0.-1..0..1....0..0..0.-1...-1..0..0..1....0..0.-1..0

..0..1.-1..0....0..0..0.-1...-1..0..1..0....0..0..0.-1....0..0..1..0

..0..0..0..0...-1..0..0..1....0..0..0..1....0..0..0..1...-1..0..0..0

..0..0..1..0....0..0.-1..0....0..0.-1..1....1.-1..1.-1....0..0..0..0

CROSSREFS

Sequence in context: A137610 A073178 A193192 * A062156 A323209 A239994

Adjacent sequences:  A226862 A226863 A226864 * A226866 A226867 A226868

KEYWORD

nonn

AUTHOR

R. H. Hardin Jun 20 2013

STATUS

approved

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Last modified May 24 06:53 EDT 2019. Contains 323529 sequences. (Running on oeis4.)