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Search: id:A002725
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| A002725 |
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Number of incidence matrices: n X (n+1) binary matrices under row and column permutations.
(Formerly M2957 N1195)
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+0
4
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| 1, 3, 13, 87, 1053, 28576, 2141733, 508147108, 402135275365, 1073376057490373, 9700385489355970183, 298434346895322960005291, 31479360095907908092817694945, 11474377948948020660089085281068730
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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a(0) = 1 by convention.
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REFERENCES
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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.
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EXAMPLE
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a(1) = 3: [0,0], [0,1], [1,1].
a(2) = 13:
000 000 000 000 001 001 001 001 001 011 011 011 111
000 001 011 111 001 010 011 110 111 011 101 111 111
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CROSSREFS
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Cf. A002623, A002727, A006148, A002728, A002724.
Sequence in context: A023037 A054420 A001831 this_sequence A097711 A114477 A116434
Adjacent sequences: A002722 A002723 A002724 this_sequence A002726 A002727 A002728
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KEYWORD
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nonn,nice
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AUTHOR
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njas
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EXTENSIONS
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More terms from Vladeta Jovovic (vladeta(AT)Eunet.yu), Feb 04 2000
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