OFFSET
1,1
LINKS
Donovan Johnson, Table of n, a(n) for n = 1..1000
EXAMPLE
Initial values attracted by 87360 (4th unitary perfect number) are collected separately in A098186.
It seems that 6 is the only initial value ending in fixed point = 6.
MATHEMATICA
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, 6]||Equal[s, 60]||Equal[s, 90], Print[{n, s}]; ta=Append[ta, n]], {n, 1, 256}]; ta = Delete[ta, 1]
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Aug 31 2004
STATUS
approved