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A005998
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Number of paraffins.
(Formerly M1740)
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0
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1, 2, 7, 14, 29, 48, 79, 116, 169, 230, 311, 402, 517, 644, 799, 968, 1169, 1386, 1639, 1910, 2221, 2552, 2927, 3324, 3769, 4238, 4759, 5306, 5909, 6540, 7231, 7952, 8737, 9554, 10439, 11358, 12349, 13376
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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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
| G.f.: (x^4+2*x^3+2*x^2+1)/(-1+x)^2/(-1+x^2)^2.
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MAPLE
| (Maple) a := n -> (Matrix([[0, -1, -4, -11, -22, -41]]).Matrix(6, (i, j)-> if (i=j-1) then 1 elif j=1 then [2, 1, -4, 1, 2, -1][i] else 0 fi)^n)[1, 1]; seq (a(n), n=1..38); [From Alois P. Heinz (heinz(AT)hs-heilbronn.de), Jul 31 2008]
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CROSSREFS
| Sequence in context: A068040 A200084 A184704 * A122751 A152944 A018437
Adjacent sequences: A005995 A005996 A005997 * A005999 A006000 A006001
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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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