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A332637 The number of n X n replace matrices: binary matrices A where the i-th row contains exactly i zeros and A[i,j] >= A[j,i] for all i < j. 0
1, 2, 8, 68, 1270, 53200, 5068960, 1109820882, 562711290616, 664773220895406 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Defined in Felsner, Definition 2.
LINKS
Stefan Felsner, On the number of arrangements of pseudolines, Discrete & Computational Geometry, 18 (1997), 257-267.
FORMULA
According to [Felsner, Theorem 2] the number is at most 2^(0.6974*n^2) for large n.
EXAMPLE
For n = 3, all nine 0-1-matrices with the correct number of zeros and ones in each row are replace matrices except
[ 1 0 1 ]
A = [ 1 0 0 ]
[ 0 0 0 ]
CROSSREFS
Sequence in context: A055547 A113087 A322495 * A239843 A099729 A123117
KEYWORD
nonn,more
AUTHOR
Günter Rote, Feb 18 2020
EXTENSIONS
a(8)-a(9) from Giovanni Resta, Feb 19 2020
a(10) from Giovanni Resta, Feb 21 2020
STATUS
approved

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Last modified March 29 05:16 EDT 2024. Contains 371264 sequences. (Running on oeis4.)