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#14 by Susanna Cuyler at Sun Apr 07 09:05:39 EDT 2019
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#13 by Joerg Arndt at Sun Apr 07 08:58:33 EDT 2019
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#12 by Jon E. Schoenfield at Sun Apr 07 04:44:59 EDT 2019
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#11 by Jon E. Schoenfield at Sun Apr 07 04:44:56 EDT 2019
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| FORMULA
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G.f.: 1 / prodProduct_{k=>=1}^{inf} (1 - x^k)^A141199(k).
Let sum_{k|n} denote a sum over all divisors k of n. Then
a(n) = (1/n) sum)*Sum_{k=1}^{..n-1} c(k) A141199(n-k),
withwhere c(n)= sum) = Sum_{k|n} k *A141199(k).
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proposed
editing
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#10 by Michel Marcus at Sun Apr 07 03:54:47 EDT 2019
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#9 by Michel Marcus at Sun Apr 07 03:54:41 EDT 2019
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| REFERENCES
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Thomas Wieder: The number of certain rankings and hierarchies formed from labeled or unlabeled elements and sets, Applied Mathematical Sciences, vol. 3, 2009, no. 55, 2707 - 2724. [From Thomas Wieder, Nov 14 2009]
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| LINKS
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Thomas Wieder, <a href="http://www.m-hikari.com/ams/ams-password-2009/ams-password53-56-2009/wiederAMS53-56-2009.pdf">The number of certain rankings and hierarchies formed from labeled or unlabeled elements and sets</a>, Applied Mathematical Sciences, vol. 3, 2009, no. 55, 2707 - 2724. [Thomas Wieder, Nov 14 2009]
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| STATUS
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approved
editing
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#8 by Alois P. Heinz at Tue Dec 16 16:18:41 EST 2014
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#7 by Alois P. Heinz at Tue Dec 16 16:18:38 EST 2014
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#6 by Alois P. Heinz at Sat Apr 21 22:03:40 EDT 2012
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#5 by Alois P. Heinz at Sat Apr 21 22:03:34 EDT 2012
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| LINKS
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Alois P. Heinz, <a href="/A144791/b144791.txt">Table of n, a(n) for n = 1..100</a>
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