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A304606
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a(n) = 54*2^n + 28 (n >= 1).
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4
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136, 244, 460, 892, 1756, 3484, 6940, 13852, 27676, 55324, 110620, 221212, 442396, 884764, 1769500, 3538972, 7077916, 14155804, 28311580, 56623132, 113246236, 226492444, 452984860, 905969692, 1811939356, 3623878684, 7247757340, 14495514652, 28991029276, 57982058524
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OFFSET
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1,1
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COMMENTS
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a(n) is the number of edges of the nanostar dendrimer G[n] from the Ashrafi et al. reference.
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LINKS
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FORMULA
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G.f.: 4*x*(34 - 41*x)/(1 - 3*x + 2*x^2).
a(n) = 3*a(n - 1) - 2*a(n - 2) for n > 2. (End)
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MAPLE
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seq(54*2^n+28, n = 1 .. 40);
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MATHEMATICA
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CoefficientList[Series[4 (34 - 41 x)/(1 - 3 x + 2 x^2), {x, 0, 33}], x] (* or *)
LinearRecurrence[{3, -2}, {136, 244}, 34] (* or *)
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PROG
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(PARI) Vec(4*x*(34 - 41*x)/(1 - 3*x + 2*x^2) + O(x^40)) \\ Colin Barker, May 23 2018
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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