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 A124447 #11 Mar 04 2018 17:43:24
%S A124447 0,1,2,3,21,5,30,12,140,16,120,18,399,99,322,48,900,533,630,60,480,
%T A124447 425,1122,72,11781,360,11102,126,4515,352,2760,192,2000,832,5406,162,
%U A124447 9405,2349,6726,240,12810,2046,7392,330,27202,4235,9660,288,66306,11656
%N A124447 a(n) = lcm(A066840(n), A124440(n)).
%e A124447 Those positive integers which are coprime to 8 and are <= 8/2, are 1 and 3. Those integers which are coprime to 8 and are between 8/2 and 8, are 5 and 7.
%e A124447 So a(8) = lcm(1+3,5+7) = lcm(4,12) = 12.
%t A124447 f1[n_] := Plus @@ Select[Range[Floor[n/2]], GCD[ #,n] == 1 &]; f2[n_] := Plus @@ Select[Range[Ceiling[n/2], n], GCD[ #, n] == 1 &];Table[LCM[f1[n], f2[n]], {n, 51}] (* _Ray Chandler_, Nov 12 2006 *)
%Y A124447 Cf. A066840, A124440, A124446.
%K A124447 nonn
%O A124447 1,3
%A A124447 _Leroy Quet_, Nov 01 2006
%E A124447 Extended by _Ray Chandler_, Nov 12 2006