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A329930
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a(n) = n!^2*(Sum_{k=1..n} 1/k).
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0
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0, 1, 6, 66, 1200, 32880, 1270080, 65862720, 4418426880, 372523898880, 38569208832000, 4811724352512000, 712008517828608000, 123312192439468032000, 24712050750746591232000, 5674212235766262988800000, 1479958528399750515916800000, 435149988031383614993203200000
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OFFSET
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0,3
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COMMENTS
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For n>=1, a(n) is the number of vertices of the harmonic polytope. See Ardila and Escobar.
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LINKS
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Table of n, a(n) for n=0..17.
Federico Ardila and Laura Escobar, The harmonic polytope, arXiv:2006.03078 [math.CO], 2020.
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FORMULA
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a(n) = A000142(n)*A000254(n).
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PROG
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(PARI) a(n) = n!^2*sum(k=1, n, 1/k);
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CROSSREFS
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Cf. A000142, A000254.
Sequence in context: A229002 A122020 A262601 * A271220 A259123 A292026
Adjacent sequences: A329927 A329928 A329929 * A329931 A329932 A329933
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KEYWORD
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nonn
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AUTHOR
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Michel Marcus, Jun 08 2020
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STATUS
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approved
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