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 A289430 #9 Jul 06 2017 16:48:56 %S A289430 1,3,18,135,1134,10287,99306,1014039,10933542 %N A289430 Sum of factorial-Catalan numbers over a certain family of decorations. %C A289430 The precise definition involves the use of certain symbols akin to the peace symbol. %H A289430 Vincent Pilaud, V. Pons, <a href="http://arxiv.org/abs/1606.09643">Permutrees</a>, arXiv preprint arXiv:1606.09643 [math.CO], 2016. %Y A289430 Cf. A289427, A289428, A289429, A289431. %K A289430 nonn,more %O A289430 0,2 %A A289430 _N. J. A. Sloane_, Jul 06 2017