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 A383227 #10 Jun 02 2025 15:29:49
%S A383227 1,2,8,48,384,4608,64512,1032192,18579456,408748032,9809952768,
%T A383227 255058771968,7141645615104,228532659683328,7770110429233152,
%U A383227 279723975452393472,10629511067190951936,446439464822019981312,19643336452168879177728,903593476799768442175488,43372486886388885224423424
%N A383227 a(n) is the product of first n even numbers not divisible by 5 (cf. A217562).
%F A383227 a(n) = Product_{i=1..n} A217562(i).
%F A383227 a(n) = Product_{i=1..n} 2*(i + floor((i-1)/4)).
%t A383227 a[n_]:=Product[2*(i + Floor[(i-1)/4]),{i,n}]; Array[a,21,0]
%Y A383227 Cf. A217562, A356858.
%K A383227 nonn
%O A383227 0,2
%A A383227 _Stefano Spezia_, Apr 20 2025