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 A126299 #6 Mar 22 2016 06:06:47 %S A126299 0,1,11,21,111,321,1111,4321,11111,23211,54321,111111,122211,324321, %T A126299 654321,1111111,1222121,2432211,3244321,7654321,11111111,22121321, %U A126299 34443211,87654321,111111111,122322121,325543321,987654321,1111111111 %N A126299 Factorial codes for the fixed points of the square of Vaillé's 1997 bijection on Dyck paths. %C A126299 From n=31 the terms cannot anymore be presented unambiguously with decimal numbers, as A126298(31)=23713, A071156(23713)=39916799 and A007623(39916799) would result the factorial expansion "T987654321", where T stands for digit "ten". %H A126299 J. Vaillé, <a href="http://dx.doi.org/10.1006/eujc.1996.0089">Une Bijection Explicative de Plusieurs Propriétés Remarquables des Ponts</a>, European J. Combin. 18 (1997), no. 1, 117-124. %F A126299 a(n) = A071158(A126298(n)). %Y A126299 Cf. A071158, A126298. %Y A126299 Superset of A126301. Number of terms of length n is given by A126295(n). %K A126299 nonn,base %O A126299 0,3 %A A126299 _Antti Karttunen_, Jan 02 2007