OFFSET
0,1
COMMENTS
This aliquot sequence starts with the least odd number such that the sequence does not repeat a term after 20 or fewer terms.
REFERENCES
R. K. Guy, Unsolved Problems in Number Theory, B6.
LINKS
T. D. Noe, Table of n, a(n) for n = 0..169
Christophe CLAVIER, Aliquot Sequences
FORMULA
a(n+1) = A001065(a(n)). - R. J. Mathar, Oct 11 2017
EXAMPLE
a(0)= 1521, a(1) = sigma(1521) - 1521 = 858.
MATHEMATICA
FixedPointList[If[# > 0, DivisorSigma[1, #] - #, 0]&, 1521] // Most (* Jean-François Alcover, Mar 28 2020 *)
CROSSREFS
KEYWORD
nonn,fini,full
AUTHOR
Robert A. Stump (bee_ess107(AT)msn.com), Sep 30 2002
STATUS
approved