This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A182161 #12 Aug 17 2020 13:17:44 %S A182161 1,1,2,12,216,10560,1297440,381013920,258918871680,398362519618560, %T A182161 1366301392119014400,10325798296570753920000, %U A182161 170397664079650720884864000,6094923358716319193283074457600,469649545161250827117772066578739200,77556106803568453086056722450983544320000 %N A182161 Number of extensional acyclic digraphs on n labeled nodes. %H A182161 S. Wagner, <a href="http://math.sun.ac.za/swagner/DigraphsFull.pdf">Asymptotic enumeration of extensional acyclic digraphs</a>, in Proceedings of the SIAM Meeting on Analytic Algorithmics and Combinatorics (ANALCO12). %F A182161 a(n) = n!*A001192(n). %Y A182161 Cf. A001192, A003024. Row sums of A182162. %K A182161 nonn %O A182161 0,3 %A A182161 _N. J. A. Sloane_, Apr 15 2012