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A000163
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Series-parallel numbers.
(Formerly M1852 N0732)
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1
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2, 8, 34, 136, 538, 2080, 7970, 30224, 113874, 426520, 1590338, 5906640, 21866794, 80725280, 297292610, 1092539736, 4007553922, 14675748416, 53663197698, 195962433328, 714734393378, 2603994002280, 9477643739746, 34463730424720
(list;
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listen;
history;
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OFFSET
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2,1
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REFERENCES
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J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 142.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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Sean A. Irvine, Table of n, a(n) for n = 2..500
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FORMULA
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G.f.: 2*(1+S)/(1-S)^3, where S = g.f. for A000084. [From Sean A. Irvine, Oct 14 2009]
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CROSSREFS
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Sequence in context: A026577 A204090 A111643 * A117616 A192402 A014445
Adjacent sequences: A000160 A000161 A000162 * A000164 A000165 A000166
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane.
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EXTENSIONS
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More terms from Sean A. Irvine, Oct 14 2009
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STATUS
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approved
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