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 A018214 Alkane (or paraffin) numbers l(13,n). 2

%I

%S 1,6,36,146,511,1512,4032,9752,21942,46252,92504,176484,323554,572264,

%T 981024,1634776,2656511,4218786,6562556,10016006,15024009,22177584,

%U 32258304,46282704,65567164,91792792,127097712,174169352

%N Alkane (or paraffin) numbers l(13,n).

%D S. M. Losanitsch, Die Isomerie-Arten bei den Homologen der Paraffin-Reihe, Chem. Ber. 30 (1897), 1917-1926.

%D Winston C. Yang (paper in preparation).

%H N. J. A. Sloane, <a href="/classic.html#LOSS">Classic Sequences</a>

%H <a href="/index/Rea#recLCC">Index to sequences with linear recurrences with constant coefficients</a>, signature (6,-10,-10,50,-34,-66,110,0,-110,66,34,-50,10,10,-6,1).

%F 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.

%F G.f.: -(5*x^4+10*x^2+1)/((x-1)^11*(x+1)^5). [_Colin Barker_, Aug 06 2012]

%K nonn,easy

%O 0,2

%A _N. J. A. Sloane_, Winston C. Yang (yang(AT)math.wisc.edu)

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