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Search: id:A069780
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%I A069780
%S A069780 1,2,2,1,2,4,2,2,1,4,2,2,2,4,4,1,2,2,2,2,4,4,2,8,1,4,2,2,2,8,2,2,4,4,4,
%T A069780 1,2,4,4,8,2,8,2,2,2,4,2,2,1,2,4,2,2,8,4,8,4,4,2,4,2,4,2,1,4,8,2,2,4,8,
%U A069780 2,2,2,4,2,2,4,8,2,2,1,4,2,4,4,4,4,8,2,4,4,2,4,4,4,4,2,2,2,1,2,8,2,8,8
%N A069780 a(n)=GCD[d(n^3),d(n)].
%F A069780 a(n)=GCD[A000005(n^3), A000005(n)]
%e A069780 Terms are usually powers of 2. Smallest number m such that A069780(m)=2^n 
               is A037992(n). The first n such that a(n) is not a power of 2 equals 
               432: a(432)=GCD[d[80621568],d[432]]=GCD[130,20]=10.
%t A069780 Table[GCD[DivisorSigma[0, n^3], DivisorSigma[0, n]], {n, 1, 500}]
%Y A069780 Cf. A000005, A037992, A069781, A069782.
%Y A069780 Sequence in context: A156260 A056671 A055076 this_sequence A066954 A144925 
               A029262
%Y A069780 Adjacent sequences: A069777 A069778 A069779 this_sequence A069781 A069782 
               A069783
%K A069780 easy,nonn
%O A069780 1,2
%A A069780 Labos E. (labos(AT)ana.sote.hu), Apr 08 2002

    
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Last modified November 29 12:46 EST 2009. Contains 167659 sequences.


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