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 A071224 #15 Apr 16 2025 04:38:18
%S A071224 4,6,24,36,10,12,14,120,144,90,220,84,286,168,75,208,459,252,570,160,
%T A071224 231,374,805,72,950,78,1080,84,1276,90,1426,96,1617,850,1785,468,1998,
%U A071224 2090,2184,2280,2378,420,2666,2772,2880,2990,3102,816,3381
%N A071224 LCM of n and n-th composite number.
%H A071224 Harvey P. Dale, <a href="/A071224/b071224.txt">Table of n, a(n) for n = 1..2500</a>
%F A071224 a(n) = n*A002808(n)/A064814(n). - _Lior Manor_, Jun 02 2002
%e A071224 a(10)=90 as 18 is the 10th composite number and 10*18/gcd(10,18)=10*18/2=90.
%t A071224 Module[{nn=100,cmps},cmps=Select[Range[nn],CompositeQ];LCM@@@Thread[ {Range[ Length[ cmps]],cmps}]] (* _Harvey P. Dale_, Jul 21 2024 *)
%K A071224 nonn
%O A071224 1,1
%A A071224 _Amarnath Murthy_, May 17 2002
%E A071224 More terms from _Reinhard Zumkeller_, May 28 2002
%E A071224 More terms from _Lior Manor_, Jun 02 2002