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A247158 Number of binary n X n matrices in which each row or column sum is at most n/2. 10
1, 1, 7, 34, 7343, 304186, 1709852332, 702998475376, 94473463102448047, 417235486592360297626, 1273060578884483984898786092, 63478599188626680785194983697744, 4243780803142765740205701619107014789924 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Andrew Howroyd, Table of n, a(n) for n = 0..15

R. J. Mathar, The number of binary nXm matrices with at most k 1's in each row or column

E. Ordentlich, F. Parvaresh, R. M. Roth, Asymptotic enumeration of binary matrices with bounded row and column sums, SIAM J. Discrete Math. 26 (4) (2012) 1550-1575.

E. Ordentlich, F. Parvaresh, R. M. Roth, Asymptotic enumeration of binary matrices with bounded row and column weights, HPL-2011-239.

EXAMPLE

a(2)=7 counts the following 2 X 2 matrices: 1 matrix with all zeros, 4 matrices where a 1 is at any of the four corners, and 2 matrices with 1's covering a diagonal.

CROSSREFS

Cf. A197458, A283500.

Sequence in context: A027683 A196968 A000829 * A285802 A340523 A061825

Adjacent sequences:  A247155 A247156 A247157 * A247159 A247160 A247161

KEYWORD

nonn

AUTHOR

R. J. Mathar, Nov 21 2014

EXTENSIONS

a(6)-a(9) from Hiroaki Yamanouchi, Nov 22 2014

a(10)-a(11) from Hiroaki Yamanouchi, Nov 26 2014

a(12) from Andrew Howroyd, May 31 2017

STATUS

approved

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Last modified August 1 22:36 EDT 2021. Contains 346408 sequences. (Running on oeis4.)