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Search: id:A053046
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| A053046 |
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EulerPhi is iterated with initial value n!; a(n) = number of terms that are not powers of 2 among the iterates. |
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+0
1
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| 0, 0, 1, 1, 1, 2, 3, 3, 5, 5, 5, 6, 7, 8, 9, 9, 9, 11, 13, 13, 15, 15, 15, 16, 16, 17, 20, 21, 22, 23, 24, 24, 25, 25, 26, 28, 30, 32, 34, 34, 34, 36, 38, 38, 40, 40, 40, 41, 43, 43, 44, 45, 46, 49, 49, 50, 53, 54, 55, 56, 57, 58, 61, 61, 62, 63, 64, 64, 65, 66, 67, 69, 71, 73, 74
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OFFSET
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1,6
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COMMENT
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Non-powers of 2 arise at the beginning of iteration chains without interruption. Analogous to A053036.
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EXAMPLE
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n=10, initial v.=3628800, the iteration chain is: {3628800,829440,221184,73728,24576, 8192,4096,2048,1024,512,256,128,64,32,16,8,4,2,1}. Its length is 19 and the 5 initial values are not powers of 2: 10!,..,24576. Thus a(10)=5.
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CROSSREFS
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A000010, A000142, A053036, A048855.
Sequence in context: A154404 A083662 A130149 this_sequence A066658 A005145 A156350
Adjacent sequences: A053043 A053044 A053045 this_sequence A053047 A053048 A053049
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Feb 25 2000
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