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A192796
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Molecular topological indices of the crown graphs
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1
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0, 28, 132, 360, 760, 1380, 2268, 3472, 5040, 7020, 9460, 12408, 15912, 20020, 24780, 30240, 36448, 43452, 51300, 60040, 69720, 80388, 92092, 104880, 118800, 133900, 150228, 167832, 186760, 207060
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OFFSET
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1,2
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COMMENTS
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Crown graphs are defined for n>=3; extended to n=1 using the closed form.
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LINKS
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FORMULA
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a(n) = 2*(n-1)*n*(4*n-1).
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MATHEMATICA
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CoefficientList[Series[4*x*(5*x+7)/(1-x)^4, {x, 0, 40}], x] (* Vincenzo Librandi, Jul 04 2012 *)
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PROG
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(Magma) I:=[0, 28, 132, 360]; [n le 4 select I[n] else 4*Self(n-1)-6*Self(n-2)+4*Self(n-3)-Self(n-4): n in [1..40]]; // Vincenzo Librandi, Jul 04 2012
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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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