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Search: id:A155043
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| A155043 |
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a(n) = 1 + a(n-sigma_0(n)), a(0)=0, sigma_0(n) number of divisors of n. |
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+0
1
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| 0, 1, 1, 2, 2, 3, 2, 4, 3, 3, 3, 4, 3, 5, 4, 5, 5, 6, 4, 7, 5, 7, 5, 8, 6, 6, 6, 9, 6, 10, 6, 11, 7, 11, 7, 12, 10, 13, 8, 13, 8, 14, 8, 15, 9, 14, 9, 15, 9, 10, 10, 16, 10, 17, 10, 17, 10, 18, 11, 19, 10, 20, 12, 19, 19, 21, 12, 22, 13, 22, 13, 23, 11, 24, 14, 23, 14, 25, 14, 26, 14, 15, 15
(list; graph; listen)
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OFFSET
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0,4
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REFERENCES
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B. Balamohan, A. Kuznetsov and S. Tanny, On the behavior of a variant of Hofstadter's Q-sequence, J. Integer Sequences, Vol. 10 (2007), #07.7.1.
John A. Pelesko, Generalizing the Conway-Hofstadter $10,000 Sequence, Journal of Integer Sequences, Vol. 7 (2004), Article 04.3.5.
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MAPLE
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with(numtheory): a := proc (n) if n = 0 then 0 else 1+a(n-tau(n)) end if end proc: seq(a(n), n = 0 .. 90); [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Jan 26 2009]
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CROSSREFS
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Cf. A004001, A005185
Sequence in context: A144370 A087050 A163870 this_sequence A065770 A086375 A107324
Adjacent sequences: A155040 A155041 A155042 this_sequence A155044 A155045 A155046
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KEYWORD
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nonn
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AUTHOR
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Ctibor O. Zizka (c.zizka(AT)email.cz), Jan 19 2009
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EXTENSIONS
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Extended by Emeric Deutsch (deutsch(AT)duke.poly.edu), Jan 26 2009
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