|
Search: id:A072890
|
|
|
| A072890 |
|
The 28-cycle of the n => sigma(n)-n process, where sigma(n) is the sum of divisors of n (A000203). |
|
+0
4
|
|
| 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; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
Called a "sociable" chain.
|
|
REFERENCES
|
P. Poulet, Parfaits, amiables et extensions, Editions Stevens, Bruxelles, 1918.
|
|
FORMULA
|
a(28+n)=a(n).
|
|
MATHEMATICA
|
f[n_]:=Plus@@Divisors[n]-n; a=7524; Table[a=f[a], {n, 0, 28}] [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Nov 01 2009]
|
|
CROSSREFS
|
Cf. A000203, A045477, A072891.
Sequence in context: A115554 A106726 A064965 this_sequence A049442 A106725 A144649
Adjacent sequences: A072887 A072888 A072889 this_sequence A072891 A072892 A072893
|
|
KEYWORD
|
fini,full,nonn
|
|
AUTHOR
|
Miklos Kristof (kristmikl(AT)freemail.hu), Jul 29 2002
|
|
|
Search completed in 0.002 seconds
|
