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A003479
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Expansion of 1/((1-x)*(1-x-2*x^3)).
(Formerly M0781)
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4
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1, 2, 3, 6, 11, 18, 31, 54, 91, 154, 263, 446, 755, 1282, 2175, 3686, 6251, 10602, 17975, 30478, 51683, 87634, 148591, 251958, 427227, 724410, 1228327, 2082782, 3531603, 5988258, 10153823, 17217030, 29193547, 49501194, 83935255, 142322350
(list;
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refs;
listen;
history;
text;
internal format)
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OFFSET
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0,2
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REFERENCES
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D. E. Daykin and S. J. Tucker, Introduction to Dragon Curves. Unpublished, 1976. See links in A003229 for an earlier version.
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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FORMULA
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MAPLE
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MATHEMATICA
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CoefficientList[Series[1/((1-x)*(1-x-2*x^3)), {x, 0, 40}], x] (* Vincenzo Librandi, Jun 12 2012 *)
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PROG
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(PARI) a(n)=([0, 1, 0, 0; 0, 0, 1, 0; 0, 0, 0, 1; -2, 2, -1, 2]^n*[1; 2; 3; 6])[1, 1] \\ Charles R Greathouse IV, Jun 23 2020
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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EXTENSIONS
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More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Mar 29 2003
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STATUS
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approved
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