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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.)