Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #2 Mar 31 2012 10:28:53
%S 0,0,0,0,0,0,0,0,1,0,1,0,2,0,1,0,2,0,3,0,2,0,4,0,3,0,2,1,6,0,7,1,3,1,
%T 4,0,7,1,3,1,7,0,8,1,3,2,10,0,8,1,5,2,12,0,7,2,6,2,12,0,12,2,5,3,8,0,
%U 14,3,7,1,16,0,16,3,5,4,12,0,19,2,9,4,19,0,12,4,9,4,19,0,13,4,10,4,13,0,20,3
%N Partial totient function phi(c, n) for c = 3: number of 3-semiprimes less than and coprime to n.
%Y Cf. A000010, A014612, A144740
%Y Cf. A036997 (phi(n) - max(phi(c, n)) over all nonnegative integers c)
%K easy,nonn
%O 1,13
%A _Reikku Kulon_, Sep 20 2008