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Search: id:A005227
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| A005227 |
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Number of atomic species of degree n which are not nontrivial substitutions.
(Formerly M1029)
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+0
3
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| 0, 1, 1, 2, 4, 6, 19, 20, 111, 116, 567, 641, 4718
(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).
J. Labelle and Y. N. Yeh, The relation between Burnside rings and combinatorial species, J. Combin. Theory, A 50 (1989), 269-284.
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FORMULA
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Define b(n), c(n): b(1)=c(0)=0. b(k)=a(k), k>1. c(k)=A000638(k), k>0. A005226(n) is Dirichlet convolution of b and c. - Christian G. Bower (bowerc(AT)usa.net), Feb 23 2006
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CROSSREFS
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Cf. A005226.
Sequence in context: A066894 A111115 A143085 this_sequence A108439 A152482 A045960
Adjacent sequences: A005224 A005225 A005226 this_sequence A005228 A005229 A005230
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KEYWORD
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nonn,hard
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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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a(8), a(11) corrected and a(12) added by Christian G. Bower (bowerc(AT)usa.net), Feb 23 2006 based on Goetz Pfeiffer's edit to A000638.
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