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 A228339 #13 Jul 10 2023 02:29:08
%S A228339 3,9,30,102,352,1230,4344,15483,55626,201246,732564,2681223,9861342,
%T A228339 36428320,135100620,502841295,1877678370,7032454470,26410804020,
%U A228339 99437742720,375260126904,1419223506516,5378236459328,20419260060462,77659985060772,295844249258796,1128738495397128,4312685074680465,16500218817839274,63209983347693924
%N A228339 Fourth differences of Catalan numbers (A000108).
%H A228339 Jocelyn Quaintance and Harris Kwong, <a href="https://www.emis.de/journals/INTEGERS/papers/n29/n29.Abstract.html">A combinatorial interpretation of the Catalan and Bell number difference tables</a>, Integers, 13 (2013), #A29.
%F A228339 From _Amiram Eldar_, Jul 10 2023: (Start)
%F A228339 a(n) = 9*(9*n^4 + 54*n^3 + 135*n^2 + 122*n + 40) * n! * binomial(2*n, n)/(n+5)!.
%F A228339 Sum_{n>=0} a(n)/4^n = 38. (End)
%t A228339 Differences[Table[CatalanNumber[n], {n, 0, 30}], 4] (* _Amiram Eldar_, Jul 10 2023 *)
%Y A228339 Cf. A000108, A000245, A026012, A033434, A059346.
%K A228339 nonn
%O A228339 0,1
%A A228339 _N. J. A. Sloane_, Aug 29 2013