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 A181645 #2 Mar 30 2012 18:59:28 %S A181645 1,-1,1,-1,-1,1,-2,-2,-1,1,-5,-5,-3,-1,1,-14,-14,-9,-4,-1,1,-42,-42, %T A181645 -28,-14,-5,-1,1,-132,-132,-90,-48,-20,-6,-1,1,-429,-429,-297,-165, %U A181645 -75,-27,-7,-1,1,-1430,-1430,-1001,-572,-275,-110,-35,-8,-1,1,-4862,-4862,-3432 %N A181645 Triangle Id-(xc(x),xc(x)), c(x) the g.f. of the Catalan numbers A000108. %C A181645 Inverse is A181644, the eigentriangle of the Catalan triangle (c(x),xc(x)), A033184. %e A181645 Triangle begins %e A181645 1, %e A181645 -1, 1, %e A181645 -1, -1, 1, %e A181645 -2, -2, -1, 1, %e A181645 -5, -5, -3, -1, 1, %e A181645 -14, -14, -9, -4, -1, 1, %e A181645 -42, -42, -28, -14, -5, -1, 1, %e A181645 -132, -132, -90, -48, -20, -6, -1, 1, %e A181645 -429, -429, -297, -165, -75, -27, -7, -1, 1 %K A181645 easy,sign,tabl %O A181645 0,7 %A A181645 _Paul Barry_, Nov 03 2010