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 A102052 #4 Mar 30 2012 18:36:44
%S A102052 1,-4,15,-58,229,-924,3795,-15822,66801,-285072,1227759,-5329938,
%T A102052 23299309,-102474004,453139947,-2013469718,8985382889,-40255260696,
%U A102052 180985860071,-816328679450,3692868722661,-16750809358364,76170701553635,-347166666620958,1585669523701729
%N A102052 Column 1 of triangle A102051, which is the matrix inverse of triangle A101275 (number of Schroeder paths).
%F A102052 G.f.: 8*(1-x)/(1+sqrt(1+4*x-4*x^2))^3.
%o A102052 (PARI) {a(n)=polcoeff(8*(1-x)/(1+sqrt(1+4*x-4*x^2+x*O(x^n)))^3,n)}
%Y A102052 Cf. A101275, A102051.
%K A102052 sign
%O A102052 0,2
%A A102052 _Paul D. Hanna_, Dec 27 2004