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Search: id:A060609
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| A060609 |
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Repeatedly apply Euler phi to n-th prime; a(n) = highest power of 2 that is seen. |
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+0
1
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| 2, 2, 4, 2, 4, 4, 16, 2, 4, 4, 8, 4, 16, 4, 4, 8, 4, 16, 8, 8, 8, 8, 16, 16, 32, 16, 32, 8, 4, 16, 4, 16, 64, 8, 8, 16, 16, 2, 16, 8, 16, 16, 8, 64, 8, 16, 16, 8, 16, 8, 16, 32, 64, 16, 256, 16, 16, 8, 16, 32, 8, 16, 32, 32, 32, 16, 32, 32, 8, 16, 64, 16, 32, 32, 4, 8, 64, 32, 64, 128
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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a(n)=A049116[A000040(n)]
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EXAMPLE
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n=100,p(100)=541, Phi-iteration chain is {541,540,144,48,16,8,4,2,1} with 9 terms. The largest power of 2 is the 5th term=16=a(100).
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CROSSREFS
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Cf. A000040, A000010, A049108, A049113, A049116, A003434.
Sequence in context: A116466 A116467 A079314 this_sequence A109526 A059214 A091820
Adjacent sequences: A060606 A060607 A060608 this_sequence A060610 A060611 A060612
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KEYWORD
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easy,nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Apr 13 2001
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