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 A304821 #10 Jul 02 2018 07:19:52
%S A304821 6,6,6,12,12,18,72,24,144,144,96,864,1728,192,12096,13824,1152,24192,
%T A304821 248832,2304,483840,1492992,18432,5806080,35831808,36864,34836480,
%U A304821 501645312,147456,69672960,15049359360,884736
%N A304821 For n > 3, a(n) = a(n-3) + lcm(a(n-3), n-2) with a(1)=6, a(2)=6, a(3)=6.
%t A304821 Fold[Append[#1, #1[[-3]] + LCM[#1[[-3]], #2 + 1]] &, {6, 6, 6}, Range@ 29] (* _Michael De Vlieger_, May 20 2018 *)
%o A304821 (PARI) Recurrence(n)={b1=6;b2=6;b3=6;list=[6,6,6];for(k=4,n,b4=b1+lcm(k-2,b1);list=concat(list,b4);b1=b2;b2=b3;b3=b4);print(list)}
%Y A304821 Cf. A135504, A217662.
%K A304821 nonn
%O A304821 1,1
%A A304821 _Pedja Terzic_, May 19 2018