%I A130533
%S A130533 0,0,2,6,13,9,2,19,2,19,2,3,4,37,8,43,47,47,53,2,6,59,61,8,71,6,79,2,5,
%T A130533 83,89,2,3,12,101,107,4,3,3,2,11
%N A130533 a(n) = smallest k such that A001358(n+1) = A001358(n) + (A001358(n) mod 
               k), or 0 if no such k exists.
%C A130533 a(n) is the weight of semiprimes. A020639(n) is the weight of natural 
               numbers. A117078(n) is the weight of primes numbers.
%H A130533 Remi Eismann, <a href="b130533.txt">Table of n, a(n) for n=1..9999</a>
%e A130533 For n = 1 we have A001358(n) = 4, A001358(n+1) = 6; there is no k such 
               that 6 - 4 = 2 = (4 mod k), hence a(1) = 0.
%e A130533 For n = 3 we have A001358(n) = 9, A001358(n+1) = 10; 2 is the smallest 
               k such that 10 - 9 = 1 = (9 mod k), hence a(3) = 2.
%e A130533 For n = 19 we have A001358(n) = 55, A001358(n+1) = 57; 53 is the smallest 
               k such that 57 - 55 = 2 = (55 mod k), hence a(19) = 53.
%Y A130533 Cf. A020639, A117078, A117563, A001223, A118534, A090369, A090368.
%Y A130533 Sequence in context: A089415 A161324 A116534 this_sequence A082722 A030416 
               A006284
%Y A130533 Adjacent sequences: A130530 A130531 A130532 this_sequence A130534 A130535 
               A130536
%K A130533 nonn
%O A130533 1,3
%A A130533 Remi Eismann (reismann(AT)free.fr), Aug 16 2007