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Search: id:A072891
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| A072891 |
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The 5-cycle of the n => sigma(n)-n process, where sigma(n) is the sum of divisors of n (A000203). |
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+0
4
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OFFSET
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1,1
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COMMENT
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Called a "sociable" chain.
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REFERENCES
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P. Poulet, Parfaits, amiables et extensions, Editions Stevens, Bruxelles, 1918.
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FORMULA
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a(5+n)=a(n).
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CROSSREFS
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Cf. A000203, A045477, A072890, A003416.
Sequence in context: A068676 A033669 A122726 this_sequence A003416 A045217 A078957
Adjacent sequences: A072888 A072889 A072890 this_sequence A072892 A072893 A072894
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KEYWORD
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fini,full,nonn
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AUTHOR
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Miklos Kristof (kristmikl(AT)freemail.hu), Jul 29 2002
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