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A183762
Number of 2 X 2 nonsingular 0..n matrices with rows and columns in increasing order.
1
2, 16, 61, 163, 359, 687, 1206, 1966, 3040, 4498, 6435, 8917, 12077, 15993, 20788, 26588, 33542, 41744, 51397, 62595, 75543, 90407, 107382, 126582, 148292, 172670, 199931, 230277, 264005, 301225, 342332, 387452, 436902, 490948, 549841, 613831
OFFSET
1,1
LINKS
EXAMPLE
Some solutions for n=2:
..0..1....0..1....1..2....0..1....1..2....1..2....0..2....0..2....0..2....0..1
..1..1....1..0....2..0....2..1....2..1....2..2....2..0....1..0....2..1....2..2
CROSSREFS
Sequence in context: A208495 A207583 A152665 * A061608 A212899 A127276
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 06 2011
STATUS
approved