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A135621 Number of prime factors of 11^n + 2 (counted with multiplicity).

%I A135621 #9 Oct 24 2016 18:32:41
%S A135621 1,1,2,2,3,1,3,3,3,1,7,3,4,3,3,2,5,2,2,3,4,3,5,3,3,3,7,3,5,6,3,2,4,3,
%T A135621 7,5,7,3,6,3,4,4,7,4,6,7,4,2,5,3,7,5,8,4,3,4,3,5,7,6,2,5,2,5,5,4,7,7
%N A135621 Number of prime factors of 11^n + 2 (counted with multiplicity).
%C A135621 a(n)=1 for n=0,1,5,9,287,8273, see A109076.
%e A135621 a(0)=1 because 11^0+2=3(prime),
%e A135621 a(1)=1 because 11^1+2=13(prime),
%e A135621 a(2)=2 because 11^2+2=123=3*41(semiprime),
%e A135621 a(3)=2 because 11^3+2=123=31*43(semiprime),
%e A135621 a(4)=3 because 11^4+2=14643=3^2*1627(3 prime factors).
%t A135621 Table[ PrimeOmega[11^n + 2] , {n,0,25}] (* _G. C. Greubel_, Oct 23 2016 *)
%o A135621 (PARI) a(n) = bigomega(11^n+2); \\ _Michel Marcus_, Oct 13 2013
%Y A135621 Cf. A109076.
%K A135621 nonn
%O A135621 0,3
%A A135621 _Zak Seidov_, Mar 03 2008