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A187462 T(n,k)=Number of (n+1)X(n+1) 0..k arrays with all the 2X2 subblocks nonsingular and the array of 2X2 subblock determinants symmetric 8
6, 50, 26, 192, 1236, 144, 512, 13726, 89618, 1272, 1126, 84048, 5098224, 11684688, 15192, 2146, 325932, 100936174, 3387715318, 6112320620, 286392, 3760, 1118854, 1061948616, 216668424092, 19708386669940, 4871877392202, 7648032, 6112 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Table starts

.........6................50................192..............512..........1126

........26..............1236..............13726............84048........325932

.......144.............89618............5098224........100936174....1061948616

......1272..........11684688.........3387715318.....216668424092.5212823523842

.....15192........6112320620.....19708386669940.7540469990506332

....286392.....4871877392202.150657364854061134

...7648032.17264863350746654

.314011868

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..40

EXAMPLE

Some k=3 solutions for 4X4

..0..2..2..0....0..2..3..3....0..2..2..3....0..2..2..2....0..2..2..0

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

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

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

CROSSREFS

Row 1 is A062801

Sequence in context: A187699 A212232 A187670 * A231270 A062801 A035290

Adjacent sequences:  A187459 A187460 A187461 * A187463 A187464 A187465

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin Mar 10 2011

STATUS

approved

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Last modified May 19 04:06 EDT 2019. Contains 323377 sequences. (Running on oeis4.)