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 A187669 Number of (n+1)X(n+1) 0..2 arrays with each 2X2 subblock nonsingular and the array of 2X2 subblock determinants symmetric about the diagonal and antidiagonal 0
 50, 550, 11282, 612204, 65533922, 18950885038 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 2 of A187670 LINKS EXAMPLE Some solutions for 4X4 ..1..0..1..2....2..0..2..1....1..1..2..0....2..2..2..2....1..0..1..0 ..2..2..0..2....2..1..0..2....1..2..1..2....2..1..0..2....1..2..0..1 ..1..0..1..2....2..0..1..1....2..1..2..1....2..0..1..2....1..0..2..1 ..0..2..0..2....1..2..0..2....0..2..1..1....1..2..2..2....0..1..0..1 CROSSREFS Sequence in context: A128954 A022147 A285044 * A160336 A231583 A156965 Adjacent sequences:  A187666 A187667 A187668 * A187670 A187671 A187672 KEYWORD nonn AUTHOR R. H. Hardin Mar 12 2011 STATUS approved

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Last modified August 13 05:18 EDT 2022. Contains 356077 sequences. (Running on oeis4.)