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.

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

Offset: 1

Author

R. H. Hardin Mar 10 2011

Keywords

• nonn
• tabl

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

Examples

			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
		

Links

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

Crossrefs

Row 1 is A062801