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A006148
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Number of 4 X n binary matrices up to row and column permutations.
(Formerly M3919)
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15
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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; refs; listen; history; internal format)
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OFFSET
| 0,2
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REFERENCES
| 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.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
| Vladeta Jovovic, Binary matrices up to row and column permutations
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FORMULA
| 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
| Cf. A002623, A002727, A006380.
Sequence in context: A183925 A122058 A191008 * A086090 A037529 A108072
Adjacent sequences: A006145 A006146 A006147 * A006149 A006150 A006151
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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 and g.f. from Vladeta Jovovic (vladeta(AT)eunet.rs), Feb 04 2000
Definition corrected by Max Alekseyev (maxale(AT)gmail.com), Feb 05 2010
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