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 A260724 #18 Aug 04 2015 10:43:02
%S A260724 2,3,2,7,5,2,31,3,109,13,97,83,8731,461,3078769,574933,206179,510583,
%T A260724 5153873111,1900169,372828179,4032506435771041,3445362972116384083,
%U A260724 49898596950715368948711529590337583,54176564592185030069557382121821
%N A260724 a(1) = 2; for n > 1 if n mod 3=0 a(n) = gpf(1 + Product_{m modulo 3=2,m<n} a(m)), if n modulo 3=1 a(n) = gpf(1 + Product_{m modulo 3=0,m<n} a(m)), if n modulo 3=2 a(n) = gpf(1 + Product_{m modulo 3=1,m<n} a(m)).
%H A260724 Anders Hellström, <a href="/A260724/b260724.txt">Table of n, a(n) for n = 1..27</a>
%o A260724 (PARI) gpf(n)=my(v=factor(n)[, 1]); v[#v];
%o A260724 first(m)={my(v=vector(m),one=2,two=2,three=1);v[1]=2;for(i=2, m,if(i%3===0,v[i]=gpf(three+1);two*=v[i],if(i%3===1,v[i]=gpf(one+1);three*=v[i],v[i]=gpf(two+1);one*=v[i])));v;}
%Y A260724 Cf. A258581
%K A260724 nonn
%O A260724 1,1
%A A260724 _Anders Hellström_, Jul 30 2015