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^15 - 80*n^13 - 300*n^12 + 1366*n^11 + 18300*n^10 + 117700*n^9 + 293220*n^8 - 4873571*n^7 - 63731100*n^6 - 168619940*n^5 + 2528179320*n^4 + 17989477164*n^3 - 56994404400*n^2 - 561199055760*n + 1856094609600)/3628800. - Vaclav Kotesovec, Apr 11 2020
MATHEMATICA
Table[(n - 4)*(n - 3)*(n - 2)*(n - 1)*n*(n^15 - 80*n^13 - 300*n^12 + 1366*n^11 + 18300*n^10 + 117700*n^9 + 293220*n^8 - 4873571*n^7 - 63731100*n^6 - 168619940*n^5 + 2528179320*n^4 + 17989477164*n^3 - 56994404400*n^2 - 561199055760*n + 1856094609600)/3628800, {n, 5, 20}] (* Wesley Ivan Hurt, Apr 12 2020 *)
CROSSREFS
KEYWORD
nonn,easy
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