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 A109045 #34 Nov 26 2022 04:02:32
%S A109045 0,4,4,12,4,20,12,28,8,36,20,44,12,52,28,60,16,68,36,76,20,84,44,92,
%T A109045 24,100,52,108,28,116,60,124,32,132,68,140,36,148,76,156,40,164,84,
%U A109045 172,44,180,92,188,48,196,100,204,52,212,108,220,56,228,116,236,60
%N A109045 a(n) = lcm(n,4).
%H A109045 Reinhard Zumkeller, <a href="/A109045/b109045.txt">Table of n, a(n) for n = 0..10000</a>
%H A109045 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,2,0,0,0,-1).
%H A109045 <a href="/index/Lc#lcm">Index entries for sequences related to lcm's</a>.
%F A109045 a(n) = 4n/gcd(n, 4).
%F A109045 a(n) = A084351(n), n > 1. - _R. J. Mathar_, Aug 20 2008
%F A109045 From _R. J. Mathar_, Apr 18 2011: (Start)
%F A109045 G.f.: 4*x*(1+x+3*x^2+x^3+3*x^4+x^5+x^6) / ( (x-1)^2*(1+x)^2*(x^2+1)^2 ).
%F A109045 a(n) = 4*n/A109008(n) = 4*A060819(n). (End)
%F A109045 Sum_{k=1..n} a(k) ~ (11/8) * n^2. - _Amiram Eldar_, Nov 26 2022
%t A109045 Table[LCM[n,4],{n,0,80}] (* _Harvey P. Dale_, May 02 2011 *)
%o A109045 (Magma) [Lcm(n,4): n in [0..100]]; // _Vincenzo Librandi_, Apr 18 2011
%o A109045 (Haskell)
%o A109045 a109045 = lcm 4 -- _Reinhard Zumkeller_, Nov 25 2013
%o A109045 (PARI) a(n) = lcm(n, 4); \\ _Michel Marcus_, Mar 07 2018
%Y A109045 Cf. A060819, A084351, A109008, A109042.
%K A109045 nonn,easy
%O A109045 0,2
%A A109045 _Mitch Harris_, Jun 18 2005