A147872 Number of consistent sets of 7 irreflexive binary order relationships over n objects.

6540, 496680, 10931760, 124318112, 934536600, 5284309680, 24238001040, 94622473440, 324833152644, 1003729086360, 2840342968320, 7458732665280, 18365400613040, 42754133712096, 94739078371680, 200943535287360, 409861294271100, 807103156903560, 1539611666989968

Offset: 5

Author

R. H. Hardin, May 04 2009

Keywords

• nonn

Links

• V. I. Rodionov, On the number of labeled acyclic digraphs, Discr. Math. 105 (1-3) (1992), 319-321.

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), A147881 (k = 8), A147883 (k = 9), A147964 (k = 10).

Column k = 7 of A081064.

Formula

a(n) = (n-4)*(n-3)*(n-2)*(n-1)*n*(n^9 + 3*n^8 - 26*n^7 - 168*n^6 - 259*n^5 + 1743*n^4 + 15044*n^3 + 40722*n^2 - 111060*n - 817320)/5040. - Vaclav Kotesovec, Apr 11 2020

Extensions

More terms from Vaclav Kotesovec, Apr 11 2020

Offset changed to n=5 by Petros Hadjicostas, Apr 11 2020