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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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2
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0, 1, 1, 2, 4, 6, 19, 20, 111, 116, 567, 641, 4718
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,4
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REFERENCES
| J. Labelle and Y. N. Yeh, The relation between Burnside rings and combinatorial species, J. Combin. Theory, A 50 (1989), 269-284.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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FORMULA
| 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
| Cf. A005226.
Sequence in context: A111115 A195328 A143085 * A185185 A108439 A193774
Adjacent sequences: A005224 A005225 A005226 * A005228 A005229 A005230
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KEYWORD
| nonn,hard
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
| 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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