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A072890 The 28-cycle of the n => sigma(n)-n process, where sigma(n) is the sum of divisors of n (A000203). 3
14316, 19116, 31704, 47616, 83328, 177792, 295488, 629072, 589786, 294896, 358336, 418904, 366556, 274924, 275444, 243760, 376736, 381028, 285778, 152990, 122410, 97946, 48976, 45946, 22976, 22744, 19916, 17716, 14316 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Called a "sociable" chain.

REFERENCES

P. Poulet, Parfaits, amiables et extensions, Editions Stevens, Bruxelles, 1918.

LINKS

Table of n, a(n) for n=1..29.

FORMULA

a(28+n) = a(n).

MATHEMATICA

f[n_]:=Plus@@Divisors[n]-n; a=7524; Table[a=f[a], {n, 0, 28}] (* Vladimir Joseph Stephan Orlovsky, Nov 01 2009 *)

NestList[DivisorSigma[1, #]-#&, 14316, 28] (* Harvey P. Dale, Oct 27 2013 *)

CROSSREFS

Cf. A000203, A001065, A045477, A072891.

Sequence in context: A115554 A106726 A064965 * A249314 A249207 A049442

Adjacent sequences:  A072887 A072888 A072889 * A072891 A072892 A072893

KEYWORD

fini,full,nonn

AUTHOR

Miklos Kristof, Jul 29 2002

STATUS

approved

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Last modified June 20 05:01 EDT 2019. Contains 324229 sequences. (Running on oeis4.)