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A006009
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Number of paraffins.
(Formerly M3513)
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1
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4, 16, 48, 108, 216, 384, 640, 1000, 1500, 2160, 3024, 4116, 5488, 7168, 9216, 11664, 14580, 18000, 22000, 26620, 31944, 38016, 44928, 52728, 61516, 71344, 82320, 94500, 108000, 122880, 139264, 157216
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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REFERENCES
| S. M. Losanitsch, Die Isomerie-Arten bei den Homologen der Paraffin-Reihe, Chem. Ber. 30 (1897), 1917-1926.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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FORMULA
| 2*(A005994(n)[ 1, 3, 9, 19, 38, 66, 110... ] + C(n, 4)[ 1, 5, 15, 35... ]).
G.f.: 4x (1 - x^3 ) / ((1 - x)^4 (1 - x^2 )^2). [From Alois P. Heinz (heinz(AT)hs-heilbronn.de), Aug 13 2008]
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MAPLE
| a := n-> (Matrix([[0$4, 4, 16, 48, 108]]). Matrix(8, (i, j)-> if (i=j-1) then 1 elif j=1 then [4, -4, -4, 10, -4, -4, 4, -1][i] else 0 fi)^n)[1, 1]; seq (a(n), n=1..32); [From Alois P. Heinz (heinz(AT)hs-heilbronn.de), Aug 13 2008]
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CROSSREFS
| 4*A007009.
Sequence in context: A055342 A174836 A050616 * A100625 A203248 A071009
Adjacent sequences: A006006 A006007 A006008 * A006010 A006011 A006012
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KEYWORD
| nonn,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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