Search: id:A136567
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%I A136567
%S A136567 0,1,1,1,1,0,1,1,1,0,1,2,1,0,0,1,1,2,1,2,0,0,1,2,1,0,1,2,1,0,1,1,0,0,0,
%T A136567 0,1,0,0,2,1,0,1,2,2,0,1,2,1,2,0,2,1,2,0,2,0,0,1,1,1,0,2,1,0,0,1,2,0,0,
%U A136567 1,2,1,0,2,2,0,0,1,2,1,0,1,1,0,0,0,2,1,1,0,2,0,0,0,2,1,2,2,0,1,0,1,2,0
%N A136567 a(n) = number of exponents occurring only once each in the prime-factorization 
               of n.
%C A136567 Records are in A006939: 1, 2, 12, 360, 75600, ..., . - Robert G. Wilson 
               v (rgwv(AT)rgwv.com), Jan 20 2008
%H A136567 Leroy Quet, <a href="http://www.prism-of-spirals.net/">Home Page</a> 
               (listed in lieu of email address)
%e A136567 4200 = 2^3 * 3^1 * 5^2 * 7^1. The exponents of the prime factorization 
               are therefore 3,1,2,1. The exponents occurring exactly once are 2 
               and 3. So a(4200) = 2.
%t A136567 f[n_] := Block[{fi = Sort[Last /@ FactorInteger@n]}, Count[ Count[fi, 
               # ] & /@ Union@fi, 1]]; f[1] = 0; Array[f, 105] - Robert G. Wilson 
               v (rgwv(AT)rgwv.com), Jan 20 2008
%Y A136567 Cf. A071625, A136566.
%Y A136567 For a(n)=0 see A130092 plus the term 1; for a(n)=1 see A000961.
%Y A136567 Sequence in context: A082858 A115953 A143379 this_sequence A109708 A035468 
               A051777
%Y A136567 Adjacent sequences: A136564 A136565 A136566 this_sequence A136568 A136569 
               A136570
%K A136567 nonn
%O A136567 1,12
%A A136567 Leroy Quet, Jan 07 2008
%E A136567 More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 20 2008

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