1,2

Numbers n for which A318880(n) = 0. - Antti Karttunen, Sep 23 2018

The sequence doesn't contain any numbers from attractor sets like A002827, A063991, A097024, A097030, etc, nor any number x such that the iteration of the map x -> A034460(x) would lead to such an attractor set (e.g., numbers in A097034 - A097037). - Antti Karttunen, Sep 24 2018, after the original author's example.

Antti Karttunen, Table of n, a(n) for n = 1..10001

di[x_] :=Divisors[x]; ta={{0}}; ud[x_] :=Part[di[x], Flatten[Position[GCD[di[x], Reverse[di[x]]], 1]]]; asu[x_] :=Apply[Plus, ud[x]]-x; nsf[x_, ho_] :=NestList[asu, x, ho] Do[g=n; s=Last[NestList[asu, n, 100]]; If[Equal[s, 0], Print[{n, s}]; ta=Append[ta, n]], {n, 1, 256}]; ta = Delete[ta, 1]

(PARI)

up_to = 10000;

A034460(n) = (sumdivmult(n, d, if(gcd(d, n/d)==1, d))-n); \\ From A034460

A318880(n) = { my(visited = Map()); for(j=1, oo, if(mapisdefined(visited, n), return(1), mapput(visited, n, j)); n = A034460(n); if(!n, return(0))); };

A097010list(up_to) = { my(v = vector(up_to), k=0, n=1); while(k<up_to, if(!A318880(n), k++; v[k] = n); n++); (v); };

v097010 = A097010list(up_to);

A097010(n) = v097010[n]; \\ Antti Karttunen, Sep 24 2018

Cf. A002827, A034460, A063991, A097024, A097030, A097031, A097032, A097033, A097034, A097035, A097036, A097037.

Cf. A003062 (complement), A318880.

Differs from A129487 for the first time at n=51, as A129487(51) = 54, but that term is lacking here, as in this sequence a(51) = 55.

Sequence in context: A034153 A004725 A129487 * A351227 A132999 A054027

Adjacent sequences: A097007 A097008 A097009 * A097011 A097012 A097013

Labos Elemer, Aug 31 2004

Edited by Antti Karttunen, Sep 24 2018

approved