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A002724
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Number of inequivalent n X n binary matrices, where equivalence means permutations of rows or columns.
(Formerly M1801 N0711)
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29
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1, 2, 7, 36, 317, 5624, 251610, 33642660, 14685630688, 21467043671008, 105735224248507784, 1764356230257807614296, 100455994644460412263071692, 19674097197480928600253198363072, 13363679231028322645152300040033513414, 31735555932041230032311939400670284689732948
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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REFERENCES
| A. Kerber, Experimentelle Mathematik, S\'{e}minaire Lotharingien de Combinatoire. Institut de Recherche Math. Avanc\'{e}e, Universit\'{e} Louis Pasteur, Strasbourg, Actes 19 (1988), 77-83.
Misek, Bohuslav; On the number of classes of strongly equivalent incidence matrices. (Czech) Casopis Pest. Mat. 89 1964 211-218.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
| M. Zivkovic, Classification of small (0,1) matrices, arXiv:mathCO/0511636
Index entries for sequences related to binary matrices
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FORMULA
| a(n) = sum {1*s_1+2*s_2+...=n, 1*t_1+2*t_2+...=n} (fix A[s_1, s_2, ...;t_1, t_2, ...]/(1^s_1*s_1!*2^s_2*s_2!*...*1^t_1*t_1!*2^t_2*t_2!*...)) where fix A[...] = 2^sum {i, j>=1} (gcd(i, j)*s_i*t_j) - Christian G. Bower (bowerc(AT)usa.net), Dec 18 2003
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CROSSREFS
| Cf. A002623, A002727, A006148, A002728, A002725, A052269, A052271, A052272, A091059.
Sequence in context: A012717 A072236 A007474 * A203900 A173827 A029990
Adjacent sequences: A002721 A002722 A002723 * A002725 A002726 A002727
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KEYWORD
| nonn,nice
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
| More terms from Vladeta Jovovic (vladeta(AT)eunet.rs), Feb 04 2000
a(15) from Herman Jamke (hermanjamke(AT)fastmail.fm), Feb 24 2008
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