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Search: id:A007563
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| A007563 |
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Number of rooted connected graphs where every block is a complete graph.
(Formerly M2751)
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+0
7
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| 0, 1, 1, 3, 8, 25, 77, 258, 871, 3049, 10834, 39207, 143609, 532193, 1990163, 7503471, 28486071, 108809503, 417862340, 1612440612, 6248778642, 24309992576, 94905791606, 371691137827, 1459935388202, 5749666477454
(list; graph; listen)
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OFFSET
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0,4
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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).
F. Harary and E. M. Palmer, Graphical Enumeration, Academic Press, NY, 1973, p. 71, (3.4.13).
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LINKS
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T. D. Noe, Table of n, a(n) for n=0..200
M. Bernstein and N. J. A. Sloane, Some canonical sequences of integers, Linear Alg. Applications, 226-228 (1995), 57-72; erratum 320 (2000), 210.
INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 167
N. J. A. Sloane, Transforms
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FORMULA
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Shifts left when Euler transform applied twice.
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MAPLE
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with (numtheory): etr:= proc(p) local b; b:= proc(n) option remember; if n=0 then 1 else (add (d*p(d), d=divisors(n)) +add (add(d*p(d), d=divisors(j)) *b(n-j), j=1..n-1))/n fi end end: b:= etr(a): c:= etr(b): a:= n-> if n=0 then 0 else c(n-1) fi: seq (a(n), n=0..25); [From Alois P. Heinz (heinz(AT)hs-heilbronn.de), Sep 06 2008]
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CROSSREFS
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Cf. A007549, A030019, A035051-A035053.
Sequence in context: A148790 A148791 A148792 this_sequence A050383 A060404 A101490
Adjacent sequences: A007560 A007561 A007562 this_sequence A007564 A007565 A007566
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KEYWORD
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nonn,nice,eigen
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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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New description from Christian G. Bower (bowerc(AT)usa.net), Oct 15 1998.
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