A188450 - OEIS

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A188450

Number of (2*n)Xn binary arrays with nonzero rows in decreasing order, no more than 3 ones in any row and exactly 2 ones in every column

0, 1, 8, 66, 722, 9955, 165252, 3221806, 72445292, 1851203574, 53113148720, 1694163830194, 59579694687012

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

COMMENTS

Row 2 of A188449

LINKS

Table of n, a(n) for n=1..13.

EXAMPLE

Some solutions for 6X3

..1..1..1....1..1..0....1..1..1....1..0..1....1..1..0....1..1..1....1..1..1

..1..0..1....1..0..1....1..0..0....1..0..0....1..0..1....1..0..0....1..1..0

..0..1..0....0..1..0....0..1..1....0..1..1....0..1..1....0..1..0....0..0..1

..0..0..0....0..0..1....0..0..0....0..1..0....0..0..0....0..0..1....0..0..0

..0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0

CROSSREFS

Sequence in context: A152275 A083385 A275230 * A121766 A052620 A052669

Adjacent sequences: A188447 A188448 A188449 * A188451 A188452 A188453

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 31 2011

STATUS

approved