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%I #17 Nov 08 2019 15:59:35
%S 0,0,0,0,1,40,35317,56150820,111359017198,278086517599356,
%T 877760741062694898,3482578978170418753715,17204168691253789080138981,
%U 104690934973509839187285618311,776311587313178356520412354767734,6942595716239018207126337605515965388
%N Number of unlabeled digraphs on n vertices such that every vertex has outdegree 4.
%H Andrew Howroyd, <a href="/A185194/b185194.txt">Table of n, a(n) for n = 1..50</a>
%H L. Travis, <a href="http://arXiv.org/abs/math.CO/9811127">[math/9811127] Graphical Enumeration: A Species-Theoretic Approach</a>
%Y Column k=4 of A329228.
%Y Cf. A001373, A129524, A185193, A185303.
%K nonn
%O 1,6
%A _Nathaniel Johnston_, Feb 08 2012
%E Terms a(10) and beyond from _Andrew Howroyd_, Nov 08 2019