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 A079145 #9 Jan 08 2018 01:47:43 %S A079145 1,3,19,195,2791,51423,1167979,32067675,1064281951,43806954183, %T A079145 2376985075939,186194963282595,22598045194449271,4259417828951807343, %U A079145 1200382884654622348699,490727012583769876310955,286998078380075662131967951,238889878466868543045084230103 %N A079145 Number of labeled semitransitive orders on n elements: (1+3)-free posets. %H A079145 M. Guay-Paquet, A. H. Morales, E. Rowland, <a href="http://arxiv.org/abs/1212.5356">Structure and enumeration of (3+1)-free posets (extended abstract)</a>, arXiv:1212.5356 [math.CO], 2012. %F A079145 E.g.f.: S(e^x-1, T(x)), where S(x, y) is the g.f. for A221494 and T(x) is the e.g.f. for A221493. [_Mathieu Guay-Paquet_, Jan 18 2013] %Y A079145 Cf. A079146 (unlabeled semitransitive orders). %K A079145 nonn,easy %O A079145 1,2 %A A079145 Detlef Pauly (dettodet(AT)yahoo.de), Dec 27 2002 %E A079145 More terms from _Mathieu Guay-Paquet_, Jan 18 2013