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 A071221 #14 Apr 16 2025 04:57:14
%S A071221 4,48,1080,60480,5544000,622702080,106661318400,28405593216000,
%T A071221 8247280940236800,3294906785089920000,1595754032207182848000,
%U A071221 840201424492187197440000,653671274699431372640256000
%N A071221 Product of next n composite numbers.
%H A071221 Harvey P. Dale, <a href="/A071221/b071221.txt">Table of n, a(n) for n = 1..224</a>
%e A071221 a(1) = 4,a(2) = 6*8 = 48 and a(3) = 9*10*12 = 1080.
%t A071221 nn=15;With[{comps=Complement[Rest[Range[(nn(nn+1))]],Prime[Range[ PrimePi[ (nn(nn+1))]]]]},Table[Times@@Take[comps,{(n(n-1))/2+1,(n(n+1))/2}],{n,nn}]] (* _Harvey P. Dale_, Dec 03 2012 *)
%t A071221 Module[{nn=200,cmps,len},cmps=Select[Range[nn],CompositeQ];len=Floor[(Sqrt[8 Length[cmps]+1]-1)/2];Times@@@TakeList[cmps,Range[len]]] (* _Harvey P. Dale_, May 25 2022 *)
%K A071221 nonn
%O A071221 1,1
%A A071221 _Amarnath Murthy_, May 17 2002
%E A071221 Corrected and extended by _Lior Manor_, Jun 02 2002