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Search: id:A018210
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| A018210 |
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Alkane (or paraffin) numbers l(9,n). |
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+0
1
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| 1, 4, 16, 44, 110, 236, 472, 868, 1519, 2520, 4032, 6216, 9324, 13608, 19440, 27192, 37389, 50556, 67408, 88660, 115258, 148148, 188552, 237692, 297115, 368368, 453376, 554064, 672792, 811920, 974304, 1162800, 1380825, 1631796
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OFFSET
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0,2
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REFERENCES
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S. M. Losanitsch, Die Isomerie-Arten bei den Homologen der Paraffin-Reihe, Chem. Ber. 30 (1897), 1917-1926.
Winston C. Yang (paper in preparation).
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LINKS
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N. J. A. Sloane, Classic Sequences
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FORMULA
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G.f.: (1+3*x^2)/(1-x)^4/(1-x^2)^3 [ njas ]
l(c, r) = 1/2 C(c+r-3, r) + 1/2 d(c, r), where d(c, r) is C((c + r - 3)/2, r/2) if c is odd and r is even, 0 if c is even and r is odd, C((c + r - 4)/2, r/2) if c is even and r is even, C((c + r - 4)/2, (r - 1)/2) if c is odd and r is odd.
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CROSSREFS
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Sequence in context: A018828 A114211 A034131 this_sequence A054498 A134139 A097125
Adjacent sequences: A018207 A018208 A018209 this_sequence A018211 A018212 A018213
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KEYWORD
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nonn
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AUTHOR
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njas, Winston C. Yang (yang(AT)math.wisc.edu)
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