A073438 - OEIS

%I #6 Oct 15 2013 22:31:27

%S 0,0,1,1,2,2,3,0,1,0,1,0,1,2,3,2,3,2,3,4,5,4,5,6,7,8,0,8,9,8,9,10,0,1,

%T 2,0,1,2,3,1,2,0,1,2,3,1,2,3,4,5,6,4,5,6,7,8,9,7,8,6,7,8,9,10,11,9,10,

%U 11,12,10,11,9,10,11,12,13,14,12,13,14,15,13,14,15,16,17,18,16,17,18

%N Remainder of division G[n]/Pi[n], where G[n] is the number of composites not exceeding n.

%F a(n)=Mod[A065855(n), A000720(n)]=Mod[n-Pi[n]-1, Pi[n]] for n>1.

%e n=100: G[100]=100-Pi[100]-1=100-25-1=74, Pi[100]=25, remainder=a(100)=Mod[74,25]=24.

%t Table[Mod[w-PrimePi[w]-1, PrimePi[w]], {w, 1, 128}]

%Y Cf. A065855, A000720, A073437.

%K nonn

%O 2,5

%A _Labos Elemer_, Jul 31 2002