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 A367369 #14 Mar 08 2025 04:20:20
%S A367369 1,1,22,1452,195800,44765000,15548960784,7634832149392,
%T A367369 5036317938475648,4297211671488276816,4605775111899791292320,
%U A367369 6058134671618508819536768,9595073255473201184093573376,18012849924775292436074080925056,39551575929026035832580350736305920
%N A367369 a(n) = A340556(2*n, n), the central terms of the second order Eulerian numbers.
%p A367369 A340556 := (n, k) -> `if`(k=0, k^n, combinat:-eulerian2(n, k-1)):
%p A367369 seq(A340556(2*n, n), n = 0..14);
%t A367369 (* Using function T[n_, k_] from A340556. *)
%t A367369 Table[T[2 k, k], {k, 0, 14}] (* _Shenghui Yang_, Mar 07 2025 *)
%o A367369 (SageMath) # Using function E2(n, k) from A340556.
%o A367369 print([E2(2*n, n) for n in (0..14)]) # _Peter Luschny_, Mar 07 2025
%Y A367369 Indexing the second-order Eulerian numbers comes in three flavors: A008517 (following Riordan and Comtet), A201637 (following Graham, Knuth, and Patashnik) and indexing like in A340556 using the definition of Gessel and Stanley.
%K A367369 nonn
%O A367369 0,3
%A A367369 _Peter Luschny_, Nov 16 2023