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A183690 Number of (n+1)X2 0..2 arrays with every 2X2 subblock nonsingular 1
50, 314, 1970, 12362, 77570, 486746, 3054290, 19165418, 120261410, 754630394, 4735243250, 29713259402, 186448243010, 1169947290266, 7341322395410, 46066190299178, 289061530659170, 1813837175689274, 11381678123719730 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A183698

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n)=5*a(n-1)+8*a(n-2)

EXAMPLE

Some solutions for 3X2

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

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

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

CROSSREFS

Sequence in context: A046656 A205620 A183698 * A221572 A124809 A261803

Adjacent sequences:  A183687 A183688 A183689 * A183691 A183692 A183693

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 06 2011

STATUS

approved

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Last modified September 25 19:48 EDT 2017. Contains 292500 sequences.