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 A343579 #22 Apr 09 2022 07:19:34
%S A343579 1,0,1,1,3,9,36,176,1030,7039,55098,486346,4780445,51787405,613045468,
%T A343579 7873065045,109021348618,1619197654575,25675094145535,432908683794379,
%U A343579 7733991639921585,145933532935469016,2900112108790279902,60543749629794205640,1324677739541613767983
%N A343579 a(n) = Sum_{k=0..floor(n/2)} |Stirling1(n - k, k)|.
%C A343579 Equals antidiagonal sums of the triangle of unsigned Stirling numbers of the first kind (A132393).
%H A343579 Seiichi Manyama, <a href="/A343579/b343579.txt">Table of n, a(n) for n = 0..451</a>
%F A343579 a(n) ~ n! / n^2. - _Vaclav Kotesovec_, Apr 09 2022
%t A343579 Table[Sum[Abs[StirlingS1[n - k, k]], {k, 0, Floor[n/2]}], {n, 0, 30}] (* _Vaclav Kotesovec_, Apr 09 2022 *)
%o A343579 (PARI) a(n) = sum(k=0, n\2, abs(stirling(n-k, k, 1))); \\ _Michel Marcus_, Apr 22 2021
%o A343579 (PARI) my(N=40, x='x+O('x^N)); Vec(sum(k=0, N, x^k*prod(j=0, k-1, j+x))) \\ _Seiichi Manyama_, Apr 08 2022
%Y A343579 Cf. A132393, A320963.
%Y A343579 Variant: A237653.
%K A343579 nonn
%O A343579 0,5
%A A343579 _Peter Luschny_, Apr 20 2021