%I #12 Oct 04 2017 14:02:03
%S 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 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 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 Values of Moebius function of the products of two (not necessarily distinct) primes (semiprimes or 2-almost primes, A001358).
%C Characteristic function for numbers n such that A001358(n) is not a square. - _Antti Karttunen_, Oct 04 2017
%H Antti Karttunen, <a href="/A072165/b072165.txt">Table of n, a(n) for n = 1..3001</a>
%H Kimberly Schneider, <a href="http://planetmath.org/?op=getobj&from=objects&name=MoebiusFunction">Moebius function.</a>
%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>
%F a(n) = A008683(A001358(n)). - _Antti Karttunen_, Oct 04 2017
%e 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 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 Cf. A001358, A008683.
%K easy,nonn
%O 1,1
%A _Jani Melik_, Jun 28 2002
%E More terms from _Antti Karttunen_, Oct 04 2017