%I #8 Jan 21 2019 19:01:55
%S 1,2,4,6,11,20,27
%N Number of distinct prime factors of 3^(3^n)+1.
%C The term omega(3^(3^6)+1) was obtained with ECM factoring.
%F a(n) = A001221(A129290(n)).
%t Table[PrimeNu[3^(3^n) + 1], {n,1,10}] (* _G. C. Greubel_, May 16 2017 *)
%o (PARI) for(x=1,6,print1( omega(3^(3^x)+1),","))
%K hard,more,nonn
%O 0,2
%A _Jorge Coveiro_, Jan 29 2006
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