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Search: id:A092694
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| A092694 |
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Product of iterated phi(n). |
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+0
2
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| 1, 1, 2, 2, 8, 2, 12, 8, 12, 8, 80, 8, 96, 12, 64, 64, 1024, 12, 216, 64, 96, 80, 1760, 64, 1280, 96, 216, 96, 2688, 64, 1920, 1024, 1280, 1024, 1536, 96, 3456, 216, 1536, 1024, 40960, 96, 4032, 1280, 1536, 1760, 80960, 1024, 4032, 1280, 32768, 1536, 79872, 216
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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A logarithmic plot of this sequence shows an unusual banded structure.
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LINKS
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T. D. Noe, Plot of A092694
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FORMULA
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a(1) = 1, a(n) = phi(n) * a(phi(n))
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EXAMPLE
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a(100) = 40960 because the iterations of phi (40, 16, 8, 4, 2, 1) have a product of 40960.
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MATHEMATICA
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nMax=100; a=Table[1, {nMax}]; Do[e=EulerPhi[n]; a[[n]]=e*a[[e]], {n, 2, nMax}]; a
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CROSSREFS
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Cf. A003434 (iterations of phi(n) needed to reach 1), A092693 (iterated phi sum).
Sequence in context: A046644 A011147 A098818 this_sequence A098984 A088560 A086328
Adjacent sequences: A092691 A092692 A092693 this_sequence A092695 A092696 A092697
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KEYWORD
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nonn
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AUTHOR
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T. D. Noe (noe(AT)sspectra.com), Mar 04 2004
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