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Search: id:A006148
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| A006148 |
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Number of 4 X n binary matrices.
(Formerly M3919)
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+0
14
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| 1, 5, 22, 87, 317, 1053, 3250, 9343, 25207, 64167, 155004, 357009, 787586, 1670643, 3419552, 6774765, 13027340, 24372942, 44462456, 79240762, 138204782, 236258358, 396409924, 653639898, 1060379169, 1694174350, 2668300758
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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M. A. Harrison, On the number of classes of binary matrices, IEEE Trans. Computers, 22 (1973), 1048-1051.
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.
B. Misek, On the number of classes of strongly equivalent incidence matrices. (Czech) Casopis Pest. Mat. 89 1964 211-218.
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LINKS
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Vladeta Jovovic, Binary matrices up to row and column permutations
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FORMULA
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G.f.: (x^20 - x^19 + 4*x^18 + 9*x^17 + 23*x^16 + 39*x^15 + 90*x^14 + 131*x^13 + 204*x^12 + 238*x^11 + 252*x^10 + 238*x^9 + 204*x^8 + 131*x^7 + 90*x^6 + 39*x^5 + 23*x^4 + 9*x^3 + 4*x^2 - x + 1)/((1 - x^4)^3*(1 - x^3)^4*(1 - x^2)^3*(1 - x)^6).
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CROSSREFS
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Cf. A002623, A002727.
Sequence in context: A058750 A058752 A122058 this_sequence A086090 A037529 A108072
Adjacent sequences: A006145 A006146 A006147 this_sequence A006149 A006150 A006151
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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 and g.f. from Vladeta Jovovic (vladeta(AT)Eunet.yu), Feb 04 2000
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