A181235 - OEIS

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A181235

Number of (3*n)Xn binary matrices with all row sums equal and all column sums equal

2, 22, 3362, 33235358, 5210265060002, 90698868503010138802

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

OFFSET

1,1

COMMENTS

Column 3 of A181236

LINKS

Table of n, a(n) for n=1..6.

EXAMPLE

Some solutions for 9X3

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

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

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

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

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

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

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

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

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

CROSSREFS

Sequence in context: A222000 A261400 A113930 * A246852 A060601 A053952

Adjacent sequences: A181232 A181233 A181234 * A181236 A181237 A181238

KEYWORD

nonn

AUTHOR

R. H. Hardin Oct 10 2010

STATUS

approved