Revision History for A066029
(Underlined text is an addition;
strikethrough text is a deletion.)
Showing entries 1-10
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#11 by N. J. A. Sloane at Tue Feb 11 19:05:22 EST 2014
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| AUTHOR
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_Joseph L. Pe (joseph_l_pe(AT)hotmail.com), _, Dec 11 2001
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Discussion
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Tue Feb 11
| 19:05
| OEIS Server: https://oeis.org/edit/global/2119
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#10 by Bruno Berselli at Sun May 19 11:59:28 EDT 2013
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#9 by Charles R Greathouse IV at Sun May 19 10:31:32 EDT 2013
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Discussion
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Sun May 19
| 10:45
| Michel Marcus: OK, no problem.
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#8 by Charles R Greathouse IV at Sun May 19 10:31:29 EDT 2013
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#7 by Charles R Greathouse IV at Sun May 19 10:30:31 EDT 2013
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| COMMENTS
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a(primep) should be 1 instead of 0 when p is an odd prime.
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| STATUS
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reviewed
editing
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Discussion
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Sun May 19
| 10:31
| Charles R Greathouse IV: At the risk of pedantry I've made a small change.
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#6 by Joerg Arndt at Sun May 19 10:21:40 EDT 2013
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#5 by Michel Marcus at Sat May 18 12:02:52 EDT 2013
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Discussion
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Sun May 19
| 10:21
| Joerg Arndt: Yes, thanks.
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#4 by Michel Marcus at Sat May 18 12:02:24 EDT 2013
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| NAME
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Number of applications of d to n needed to reach a fixed point of d (i.e. 1 or 2), where d(n) = number of divisors of n.
Incorrect version of A036459.
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| DATA
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0, 0, 1, 2, 1, 3, 1, 3, 2, 3, 1, 4, 1, 3, 3, 2, 1, 4, 1, 4, 3, 3, 1, 4, 2, 3, 3, 4, 1, 4, 1, 4, 3, 3, 3, 3, 1, 3, 3, 4, 1, 4, 1, 4, 4, 3, 1, 4, 2, 4, 3, 4, 1, 4, 3, 4, 3, 3, 1, 5, 1, 3, 4, 2, 3, 4, 1, 4, 3, 4, 1, 5, 1, 3, 4, 4, 3, 4, 1, 4
0, 0, 1, 2, 1, 3, 0, 3, 2, 3, 0, 4, 0, 3, 3, 2, 0, 4, 0, 4, 3, 3, 0
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| COMMENTS
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a(prime) should be 1 instead of 0.
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| FORMULA
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a(1) = 0; a(2) = 0; a(n) = 0 if n > 2 is prime; a(n) = 1 + a(d(n)) if n > 2 is composite.
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| EXAMPLE
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a(1) = a(2) = 0 since 1 and 2 are fixed points of d (d(1) = 1, d(2) = 2). a(3) = 1 since d(3) = 2. a(4) = 2 since d(d(4)) = d(3) = 2. a(6) = 3 since d(d(d(6))) = d(d(4)) = d(3) = 2.
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| PROG
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(PARI) a(n) = {nb = 0; while((n != 1) && (n != 2), n = numdiv(n); nb++; ); return (nb); } \\ Michel Marcus, May 18 2013
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| KEYWORD
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nonn,changed
dead
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| STATUS
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proposed
editing
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Discussion
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Sat May 18
| 12:02
| Michel Marcus: OK like this ?
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#3 by Michel Marcus at Sat May 18 11:15:29 EDT 2013
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Discussion
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Sat May 18
| 11:20
| Joerg Arndt: Yes, incorrect version of A036459
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#2 by Michel Marcus at Sat May 18 11:07:16 EDT 2013
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| DATA
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0, 0, 1, 2, 1, 3, 1, 3, 2, 3, 1, 4, 1, 3, 3, 2, 1, 4, 1, 4, 3, 3, 1, 4, 2, 3, 3, 4, 1, 4, 1, 4, 3, 3, 3, 3, 1, 3, 3, 4, 1, 4, 1, 4, 04, 3, 1, 4, 2, 4, 3, 4, 1, 4, 03, 4, 03, 3, 1, 5, 1, 3, 4, 2, 3, 4, 01, 4, 03, 4, 1, 5, 1, 3, 4, 4, 3, 4, 1, 04
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| PROG
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(PARI) a(n) = {nb = 0; while((n != 1) && (n != 2), n = numdiv(n); nb++; ); return (nb); } \\ Michel Marcus, May 18 2013
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| STATUS
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approved
editing
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Discussion
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Sat May 18
| 11:15
| Michel Marcus: I think we have an incorrect version of A036459.
a(n) should be 1 when n is prime, because 1 application of d to a prime number will give result 2 (fixed point).
Whereas data and comment say a(prime)=0.
Also note that a(3) was 1.
No ?
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