Search: id:A114707
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%I A114707
%S A114707 1,2,3,4,5,7,7,8,9,11,11,13,13,15,15,16,17,19,19,21,21,23,23,25,25,27,
%T A114707 27,29,29,32,33,34,36,37,39,40,41,43,45,46,47,50,51,53,55,57,58,59,60,
%U A114707 60,61,63,64,65,66,67,69,71,72,73,74,75,76,76,78,79,80,81,82,84,85,87
%N A114707 a(1)=1. For n>1, a(n) = a(n-1) + (number of distinct primes dividing 
               n but not a(n-1)).
%C A114707 Number of distinct primes dividing n but not A114707(n-1) is A114708(n).
%C A114707 a(10^k), k=0..6: 1, 11, 130, 1691, 19819, 220501, 2398245. - Robert G. 
               Wilson v Dec 28 2005.
%H A114707 Leroy Quet, <a href="http://www.prism-of-spirals.net/">Home Page</a> 
               (listed in lieu of email address)
%e A114707 a(11) = 11. Since 2 and 3 are the 2 distinct primes that divide 12 and 
               neither divides 11, a(12) is 2 greater than a(11), a(12) = 13.
%t A114707 a[1] = 1; a[n_] := a[n] = a[n - 1] + Length@Complement[First /@ FactorInteger@n, 
               First /@ FactorInteger@a[n - 1]]; Array[a, 72] (* Robert G. Wilson 
               v *)
%o A114707 (PARI) {print1(a=1,",");for(n=2,72,print1(a=a+#setminus(Set(factor(n)[,
               1]),Set(factor(a)[,1])),","))} (Brockhaus)
%Y A114707 Cf. A114708.
%Y A114707 Sequence in context: A082025 A076034 A034152 this_sequence A000015 A122411 
               A117174
%Y A114707 Adjacent sequences: A114704 A114705 A114706 this_sequence A114708 A114709 
               A114710
%K A114707 nonn
%O A114707 1,2
%A A114707 Leroy Quet Dec 26 2005
%E A114707 More terms from Klaus Brockhaus (klaus-brockhaus(AT)t-online.de) and 
               Robert G. Wilson v (rgwv(at)rgwv.com), Dec 27 2005

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