Search: id:A053579
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%I A053579
%S A053579 4,6,8,12,14,16,24,28,32,48,56,62,64,96,112,124,128,192,224,248,254,
%T A053579 256,384,448,496,508,512,768,896,992,1016,1024,1536,1792,1984,2032,
%U A053579 2048,3072,3584,3968,4064,4096,6144,7168,7936,8128,8192,12288,14336
%N A053579 Composite numbers whose cototient (A051953) is a power of 2.
%e A053579 If n=3*2^s, cototient[n]=3*2^s-2*2^(s-1)=2^(s+1); if n=7*2^s, cototient[n]=(7-6)*2^(s-1)=2^(s+2). 
               If cototient[x]=32768, then arguments are 3*16384,7*8192,31*2048,
               127*512,8191*8 and 65536. If n=(2^w)*q, where q is a Mersenne prime, 
               then Phi(n)=(q-1)*2^(w-1) and the cototient(n)= is 2^(w-1)*(2q-q+1)=2^(w-1)*(q+1)=2^(w-1+s).
%Y A053579 Cf. A051953.
%Y A053579 Sequence in context: A090697 A107303 A028876 this_sequence A074121 A055670 
               A141096
%Y A053579 Adjacent sequences: A053576 A053577 A053578 this_sequence A053580 A053581 
               A053582
%K A053579 nonn
%O A053579 1,1
%A A053579 Labos E. (labos(AT)ana.sote.hu), Jan 18 2000

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