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

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A008887 Aliquot sequence starting at 60. 2
 60, 108, 172, 136, 134, 70, 74, 40, 50, 43, 1, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS The sum-of-divisor function A000203 and aliquot parts A001065 are defined only for positive integers, so the trajectory ends when 0 is reached, here at index 11. - M. F. Hasler, Feb 24 2018 REFERENCES R. K. Guy, Unsolved Problems in Number Theory, B6. LINKS Christophe CLAVIER, Aliquot Sequences FORMULA a(n+1) = A001065(a(n)). - R. J. Mathar, Oct 11 2017 MAPLE f := proc(n) option remember; if n = 0 then 60; else sigma(f(n-1))-f(n-1); fi; end: MATHEMATICA NestList[If[#==0, 0, DivisorSigma[1, #]-#]&, 60, 80] (* Harvey P. Dale, Nov 29 2013 *) PROG (PARI) a(n, a=60)=for(i=1, n, a=sigma(a)-a); a \\ Will raise an error for n > 11, in agreement with the definition. - M. F. Hasler, Feb 24 2018 CROSSREFS Cf. A008885 (starting at 30), ..., A008892 (starting at 276), A098007 (length of aliquot sequences). Sequence in context: A039398 A044001 A258700 * A217738 A182683 A174601 Adjacent sequences:  A008884 A008885 A008886 * A008888 A008889 A008890 KEYWORD nonn,fini,full AUTHOR EXTENSIONS Edited by M. F. Hasler, Feb 24 2018 STATUS approved

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.

Last modified December 5 05:57 EST 2021. Contains 349531 sequences. (Running on oeis4.)