login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A097037 Initial values for iteration of A063919(x) function such that iteration ends in a 2-cycle, i.e., "attracted" by unitary amicable numbers, A063991. 15

%I

%S 102,114,126,388,436,484,812,866,1020,1036,1040,1116,1140,1196,1260,

%T 1380,1500,1524,1532,1552,1618,1644,1716,1724,1726,1744,1916,2020,

%U 2066,2068,2324,2368,2386,2486,2592,2684,2880,2924,3032,3098,3120,3124,3136

%N Initial values for iteration of A063919(x) function such that iteration ends in a 2-cycle, i.e., "attracted" by unitary amicable numbers, A063991.

%H Amiram Eldar, <a href="/A097037/b097037.txt">Table of n, a(n) for n = 1..1000</a>

%e n = 866: list = {866, 436, 114, 126, 114} ending in 2-cycle of [114, 126].

%t s[n_] := If[n > 1, Times @@ (1 + Power @@@ FactorInteger[n]) - n, 0]; useq[n_] := Most[NestWhileList[s, n, UnsameQ, All]]; amiQ[k_] := Module[{s1 = s[k]}, s1 != k && s[s1] == k]; aQ[n_] := amiQ[Last[useq[n]]]; Select[Range[5000], aQ] (* _Amiram Eldar_, Apr 06 2019 *)

%Y Cf. A002827, A063919, A063991, A097024, A097030-A097036.

%K nonn

%O 1,1

%A _Labos Elemer_, Aug 30 2004

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 17 15:12 EST 2020. Contains 330958 sequences. (Running on oeis4.)