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 A134714 #14 Oct 06 2024 16:13:13
%S A134714 1,12,51442,13242914304862,16796587862080127429002674440,
%T A134714 96948453535767012964479047763870017672631906564120420,
%U A134714 2446626702091482563640343059613650128990414732448619464014521836735307215269533550916004
%N A134714 Concatenation of next n Catalan numbers.
%H A134714 Harvey P. Dale, <a href="/A134714/b134714.txt">Table of n, a(n) for n = 1..15</a>
%t A134714 Module[{nn=50,cn},cn=CatalanNumber[Range[0,nn]];Table[ FromDigits[ Flatten[ IntegerDigits/@ Take[cn,{(n(n+1))/2+1,((n+1)(n+2))/2}]]],{n,0,Floor[ (Sqrt[ 8*nn+1]-1)/2]-1}]] (* _Harvey P. Dale_, May 15 2014 *)
%t A134714 Module[{nn=8},FromDigits[Flatten[IntegerDigits/@#]]&/@Rest[TakeList[CatalanNumber[Range[0,(nn(nn+1))/2-1]],Range[0,nn-1]]]] (* _Harvey P. Dale_, Oct 06 2024 *)
%Y A134714 Cf. A053067, A053068, A133013. Catalan numbers: A000108.
%K A134714 easy,nonn,base
%O A134714 1,2
%A A134714 _Omar E. Pol_, Nov 12 2007
%E A134714 Edited by _Charles R Greathouse IV_, Apr 25 2010