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Search: id:A096852
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| A096852 |
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a(n) is the length of terminal cycle of the trajectory of f(x)=phi(sigma(x)) if started at 2^n. |
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+0
11
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| 1, 1, 2, 1, 3, 2, 2, 1, 2, 2, 6, 2, 1, 6, 2, 1, 2, 3, 11, 11, 2, 2, 15, 15, 18, 18, 18, 18, 12, 12, 12, 1
(list; graph; listen)
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OFFSET
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0,3
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EXAMPLE
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n=18: start = 262144 and the corresponding 11-cycle is 262144, 524286, [368640, 381024, 326592, 550368, 435456, 580608, 851840, 552960, 524160, 442368, 432000], 368640, ...
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MATHEMATICA
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g[n_] := EulerPhi[ DivisorSigma[1, n]]; f[n_] := Block[{lst = NestWhileList[g, n, UnsameQ, All]}, -Subtract @@ Flatten[ Position[lst, lst[[ -1]]]]]; Table[ f[2^n], {n, 0, 20}]
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CROSSREFS
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Cf. A095952, A095953, A095954, A095955, A095956, A096887, A096888, A096889, A096890, A096849, A096850.
Sequence in context: A136662 A023595 A057515 this_sequence A096857 A090000 A109082
Adjacent sequences: A096849 A096850 A096851 this_sequence A096853 A096854 A096855
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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), Jul 16 2004
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EXTENSIONS
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Edited, corrected and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Jul 17 2004
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