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A098192 Terms in a specific cycle of length 29 of the map x->A098189(x). 3
2206, 2210, 2932, 2950, 3394, 3398, 3400, 3402, 3520, 3768, 3844, 4240, 4440, 4516, 4778, 4782, 4828, 4870, 4884, 6428, 6484, 6840, 7056, 7624, 7680, 7984, 8560, 9072, 10264 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Iteration of the map x -> A098189(x) enters cycles of various lengths.

The 29 terms in the first cycle where A098190(x)=29 are listed here in ascending order; the example section of A098190 shows them in the mapping order.

See other attractors in A098191-A098195.

LINKS

Table of n, a(n) for n=1..29.

EXAMPLE

The cycle follows the mapping 3768 -> 4440 -> ... -> 2210-> 3768 (returning to the first element).

This cycle is entered, for example, if the mapping is started at x=246 (Cf. A098190).

MATHEMATICA

Function[s, Union@ Drop[s, #] &@ Count[DeleteDuplicates@ Map[Position[s, #] &, s], k_ /; Length@ k == 1]]@ NestList[Function[n, DivisorSum[n, # &, CoprimeQ[#, n/#] &] - EulerPhi@n], 246, 10^3] (* Michael De Vlieger, Mar 01 2017 *)

PROG

(PARI) A098189(n)=my(f=factor(n)); prod(k=1, #f~, f[k, 1]^f[k, 2]+1) - eulerphi(f)

a(n)=if(n>1, A098189(n-1), 2206) \\ Charles R Greathouse IV, Mar 01 2017

CROSSREFS

Cf. A063919, A098189, A098190, A098191, A098193, A098194, A098195.

Sequence in context: A252397 A252392 A175915 * A004931 A004951 A004971

Adjacent sequences:  A098189 A098190 A098191 * A098193 A098194 A098195

KEYWORD

nonn,fini,full

AUTHOR

Labos Elemer, Sep 03 2004

EXTENSIONS

Edited by R. J. Mathar, May 15 2009

STATUS

approved

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Last modified August 5 12:52 EDT 2021. Contains 346469 sequences. (Running on oeis4.)