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Search: id:A001429
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| A001429 |
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Number of n-node connected unicyclic graphs.
(Formerly M1438 N0568)
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+0
14
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| 1, 2, 5, 13, 33, 89, 240, 657, 1806, 5026, 13999, 39260, 110381, 311465, 880840, 2497405, 7093751, 20187313, 57537552, 164235501, 469406091, 1343268050, 3848223585, 11035981711, 31679671920, 91021354454, 261741776369
(list; graph; listen)
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OFFSET
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3,2
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
M. L. Stein and P. R. Stein, Enumeration of Linear Graphs and Connected Linear Graphs up to $p = 18$ Points. Report LA-3775, Los Alamos Scientific Laboratory of the University of California, Los Alamos, NM, Oct 1967.
J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 150.
R. C. Read and R. J. Wilson, An Atlas of Graphs, Oxford, 1998.
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LINKS
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Washington G. Bomfim, A picture of the twenty one unicycles with 3,4,5 and 6 vertices
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FORMULA
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a(n) = A068051(n) - A027852(n) - A000081(n).
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CROSSREFS
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Next-to-main diagonal of A054924. Cf. A000055.
Sequence in context: A007020 A080888 A052988 this_sequence A148288 A112841 A104589
Adjacent sequences: A001426 A001427 A001428 this_sequence A001430 A001431 A001432
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KEYWORD
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nonn,nice
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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More terms from R. C. Read (rcread(AT)math.uwaterloo.ca).
Corrected a(27), more terms, formula from Christian G. Bower (bowerc(AT)usa.net), Feb 12 2002
Edited by Charles R Greathouse IV (charles.greathouse(AT)case.edu), Oct 05 2009
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