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 A154604 #22 May 31 2024 05:47:40
%S A154604 1,1,3,54,9720,26244000,1488034800000,2362404048480000000,
%T A154604 135019896025206528000000000,347259290825980971841536000000000000,
%U A154604 49121618545275670528799969525760000000000000000
%N A154604 Hankel transform of reduced tangent numbers.
%C A154604 Hankel transform of A002105 (with interpolated zeros).
%C A154604 Hankel transform of A154603.
%H A154604 G. C. Greubel, <a href="/A154604/b154604.txt">Table of n, a(n) for n = 0..34</a>
%H A154604 Paul Barry, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL15/Barry3/barry84r2.html">A Note on Three Families of Orthogonal Polynomials defined by Circular Functions, and Their Moment Sequences</a>, Journal of Integer Sequences, Vol. 15 (2012), #12.7.2. - _N. J. A. Sloane_, Dec 27 2012
%F A154604 a(n) = Product_{k=1..n} C(k+1,2)^(n-k+1).
%F A154604 a(n) ~ n^(n^2 + 3*n + 7/3) * Pi^(n + 3/2) / (A^2 * 2^((n^2 - n - 3)/2) * exp(3*n^2/2 + 3*n - 1/6)), where A is the Glaisher-Kinkelin constant A074962. - _Vaclav Kotesovec_, Nov 13 2022
%t A154604 Table[Product[(k*(k+1)/2)^(n - k + 1), {k, 1, n}], {n, 0, 12}] (* _Vaclav Kotesovec_, Nov 13 2022 *)
%o A154604 (PARI) a(n) = prod(k=1, n, binomial(k+1,2)^(n-k+1)); \\ _Michel Marcus_, Nov 13 2022
%o A154604 (Magma) [n eq 0 select 1 else (&*[(Binomial(k+1,2))^(n-k+1): k in [1..n]]): n in [0..15]]; // _G. C. Greubel_, May 30 2024
%o A154604 (SageMath) [product((binomial(k+1,2))^(n-k+1) for k in range(1,n+1)) for n in range(16)] # _G. C. Greubel_, May 30 2024
%Y A154604 Cf. A002105, A154603.
%K A154604 easy,nonn
%O A154604 0,3
%A A154604 _Paul Barry_, Jan 12 2009