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A072165 Values of Moebius function of the products of two (not necessarily distinct) primes (semiprimes or 2-almost primes, A001358).

%I A072165 #12 Oct 04 2017 14:02:03
%S A072165 0,1,0,1,1,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
%T A072165 1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,1,
%U A072165 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1
%N A072165 Values of Moebius function of the products of two (not necessarily distinct) primes (semiprimes or 2-almost primes, A001358).
%C A072165 Characteristic function for numbers n such that A001358(n) is not a square. - _Antti Karttunen_, Oct 04 2017
%H A072165 Antti Karttunen, <a href="/A072165/b072165.txt">Table of n, a(n) for n = 1..3001</a>
%H A072165 Kimberly Schneider, <a href="http://planetmath.org/?op=getobj&amp;from=objects&amp;name=MoebiusFunction">Moebius function.</a>
%H A072165 <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>
%F A072165 a(n) = A008683(A001358(n)). - _Antti Karttunen_, Oct 04 2017
%e A072165 For n = 2995, A001358(2995) = 11449 = 107^2, and as Moebius mu is zero for squares, we have a(2995) = 0. - _Antti Karttunen_, Oct 04 2017
%p A072165 semiprimes := proc(d_n) local a,i; a := [ ]; for i from 1 to d_n do if((tau(i) = 3) or ((mobius(i) <> 0) and (tau(i) = 4))) then a := [ op(a), mobius(i) ]; fi; od: RETURN(a); end;
%Y A072165 Cf. A001358, A008683.
%K A072165 easy,nonn
%O A072165 1,1
%A A072165 _Jani Melik_, Jun 28 2002
%E A072165 More terms from _Antti Karttunen_, Oct 04 2017