%I A156542
%S A156542 0,1,1,1,1,2,0,1,1,2,1,2,0,1,2,1,0,2,0,2,1,2,1,2,1,1,1,1,1,3,0,1,2,1,1,
%T A156542 2,0,1,1,2,1,2,0,2,2,2,0,2,0,2,1,1,1,2,2,1,1,2,0,3,0,1,1,1,1,3,0,1,2,2,
%U A156542 0,2,0,1,2,1,1,2,0,2,1,2,1,2,1,1,2,2,1,3,0,2,1,1,1,2,0,1,2,2,0,2,0,1,2
%N A156542 Number of distinct Sophie Germain prime factors of n.
%C A156542 a(n) <= A001221(n));
%C A156542 a(A156541(n)) = A001221(A156541(n)); a(A156543(n)) = 0;
%C A156542 a(A005384(n)) = 1; a(A053176(n)) = 0.
%H A156542 R. Zumkeller, <a href="b156542.txt">Table of n, a(n) for n = 1..10000</
               a>
%Y A156542 Sequence in context: A025911 A060184 A055639 this_sequence A066360 A061358 
               A025866
%Y A156542 Adjacent sequences: A156539 A156540 A156541 this_sequence A156543 A156544 
               A156545
%K A156542 nonn
%O A156542 1,6
%A A156542 Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 10 2009