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 A355292 #14 Jul 01 2022 03:30:09
%S A355292 1,2,7,34,208,1521,12871,123306,1316316,15471114,198319614,2751524557,
%T A355292 41058030388,655427422651,11142214939181,200919300509214,
%U A355292 3829751956014084,76928721540858772,1624015067086462504,35942784684670110710,832134062464902004336
%N A355292 a(n) = Sum_{k=1..n} |Stirling1(n,k)| * Catalan(k-1).
%t A355292 Table[Sum[Abs[StirlingS1[n,k]] * CatalanNumber[k-1], {k,1,n}], {n,1,20}] (* _Vaclav Kotesovec_, Jul 01 2022 *)
%o A355292 (PARI) a(n) = sum(k=1, n, abs(stirling(n, k, 1))*binomial(2*k-2, k-1)/k);
%Y A355292 Cf. A000108, A052851, A086662.
%K A355292 nonn
%O A355292 1,2
%A A355292 _Seiichi Manyama_, Jun 27 2022