A147881 Number of consistent sets of 8 irreflexive binary order relationships over n objects.

3330, 750810, 31528980, 572121396, 6186026736, 47056700160, 277413461820, 1346956001820, 5610483560682, 20631960791442, 68410542640440, 207816360293880, 585602287143120, 1545890870506608, 3853704950392968, 9131773574418120, 20681704245537090, 44975479946588730

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), A147872 (k = 7), A147883 (k = 9), A147964 (k = 10).

Column k = 8 of A081064.

Formula

a(n) = (n-4)*(n-3)*(n-2)*(n-1)*n*(n^11 + 2*n^10 - 43*n^9 - 226*n^8 - 21*n^7 + 5110*n^6 + 36247*n^5 + 91954*n^4 - 612172*n^3 - 5449152*n^2 - 2743020*n + 82544280)/40320. - 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