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A187461 Number of (n+1)X(n+1) 0..4 arrays with all the 2X2 subblocks nonsingular and the array of 2X2 subblock determinants symmetric 0
512, 84048, 100936174, 216668424092, 7540469990506332 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 4 of A187462

LINKS

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

EXAMPLE

Some solutions for 4X4

..0..1..1..2....0..1..0..2....0..1..2..1....0..1..0..4....0..1..0..2

..1..0..1..4....1..0..1..0....1..0..2..0....1..0..1..0....1..0..1..3

..1..1..1..0....1..1..0..3....1..2..3..1....4..1..4..3....0..1..1..2

..2..4..0..1....3..1..3..1....2..2..4..3....4..0..3..1....2..1..0..3

CROSSREFS

Sequence in context: A186797 A183815 A013701 * A291461 A328200 A181244

Adjacent sequences:  A187458 A187459 A187460 * A187462 A187463 A187464

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 10 2011

STATUS

approved

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Last modified December 6 22:42 EST 2021. Contains 349567 sequences. (Running on oeis4.)