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Moebius function of even interprimes (A072568).
0

%I #2 Mar 31 2012 10:24:25

%S 1,0,0,1,-1,1,-1,0,0,0,0,0,0,1,-1,0,0,1,-1,0,0,-1,0,-1,0,0,-1,0,0,0,0,

%T 0,-1,1,0,-1,0,1,-1,0,0,0,0,1,0,0,0,-1,0,1,0,0,-1,0,0,1,1,-1,0,0,0,0,

%U 0,1,1,-1,-1,-1,0,0,0,-1,-1,0,-1,0,0,0,0,0,1,-1,0,-1,0,0,0,0,-1,0,-1,0,1,1

%N Moebius function of even interprimes (A072568).

%p ts_fip_sod:=proc(n) local i,an,tren: an:=[ ]: for i from 2 to n do tren:=(ithprime(i)+ithprime(i+1))/2: if (tren mod 2 = 0) then an:=[ op(an), numtheory[mobius](tren) ]: fi: od: RETURN(an) end: ts_fip_sod(1000);

%Y Cf. A008683.

%K sign

%O 1,1

%A _Jani Melik_, Nov 24 2009