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URL: https://oeis.org/A147883

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A147883
Number of consistent sets of 9 irreflexive binary order relationships over n objects.
8
960, 838130, 71331470, 2134043800, 33969932808, 353530511420, 2710992616420, 16512265636680, 83974746129560, 369225271340926, 1439572248244130, 5072665106738320, 16393720098232880, 49158099955813080, 138052747638032104, 365886966555545840, 920991546926843280
OFFSET
5,1
LINKS
V. I. Rodionov, On the number of labeled acyclic digraphs, Discr. Math. 105 (1-3) (1992), 319-321.
FORMULA
a(n) = (n-4)*(n-3)*(n-2)*(n-1)*n*(n^13 + n^12 - 61*n^11 - 271*n^10 + 501*n^9 + 10539*n^8 + 69721*n^7 + 170899*n^6 - 1975510*n^5 - 21334612*n^4 - 30150228*n^3 + 619527780*n^2 + 1942605000*n - 10974342960)/362880. - Vaclav Kotesovec, Apr 11 2020
CROSSREFS
Related sequences for the number of consistent sets of k irreflexive binary order relationships over n objects: A147796 (k = 3), A147817 (k = 4), A147821 (k = 5), A147860 (k = 6), A147872 (k = 7), A147881 (k = 8), A147964 (k = 10).
Column k = 9 of A081064.
Sequence in context: A278011 A282012 A378469 * A166964 A316337 A274120
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 04 2009
EXTENSIONS
More terms from Vaclav Kotesovec, Apr 11 2020
Offset changed to n=5 by Petros Hadjicostas, Apr 11 2020
STATUS
approved