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