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 A055861 #9 Jan 01 2018 04:24:21 %S A055861 0,0,6,48,500,6480,100842,1835008,38263752,900000000,23579476910, %T A055861 681091006464,21505924728444,737020860878848,27246730957031250, %U A055861 1080863910568919040,45798768824157052688,2064472028642102280192 %N A055861 Essentially A053506 but with leading 0 (instead of 1) and offset 0. %F A055861 a(0) = 0 = a(1); a(n) = n*(n+1)^(n-1), n >= 2. %F A055861 E.g.f.: -x + W(-x)^2/((1+W(-x))*x) = ((d/dx)W(-x)^2)/2-x, W(x) principal branch of Lambert's function. %Y A055861 Third column of triangle A055858. %Y A055861 Cf. A053506, A000312, A000169, A055860. %K A055861 nonn,easy %O A055861 0,3 %A A055861 _Wolfdieter Lang_, Jun 20 2000