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 A363254 #7 May 24 2023 07:33:10
%S A363254 1,3,12,93,816,9264,122028,1863849,32001504,614224272,12989299596,
%T A363254 300599511744,7550646317520,204694926767040,5955892801274796,
%U A363254 185160666502244433,6125200081143892800,214838236392631067424,7963817560398871790604,311101474513327693885056
%N A363254 Product_{n>=1} (1 + a(n)*x^n) = 1 + 1!!*x + 3!!*x^2 + 5!!*x^3 + 7!!*x^4 + ...
%t A363254 A[m_, n_] := A[m, n] = Which[m == 1, (2 n - 1)!!, m > n >= 1, 0, True, A[m - 1, n] - A[m - 1, m - 1] A[m, n - m + 1]]; a[n_] := A[n, n]; a /@ Range[1, 20]
%Y A363254 Cf. A001147, A158094, A305868, A305870, A363255.
%K A363254 nonn
%O A363254 1,2
%A A363254 _Ilya Gutkovskiy_, May 23 2023