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Search: id:A007448
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| A007448 |
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Knuth's sequence (or Knuth numbers): a(n+1) = 1 + min ( 2 a[ n/2 ], 3 a[ n/3 ] ).
(Formerly M2276)
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+0
5
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| 1, 3, 3, 4, 7, 7, 7, 9, 9, 10, 13, 13, 13, 15, 15, 19, 19, 19, 19, 21, 21, 22, 27, 27, 27, 27, 27, 28, 31, 31, 31, 39, 39, 39, 39, 39, 39, 39, 39, 40, 43, 43, 43, 45, 45, 46, 55, 55, 55, 55, 55, 55, 55, 55, 55, 57, 57, 58, 63, 63, 63, 63, 63, 64, 67, 67, 67, 79, 79, 79, 79
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
R. L. Graham, D. E. Knuth and O. Patashnik, Concrete Mathematics. Addison-Wesley, Reading, MA, 1990, p. 78.
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LINKS
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T. D. Noe, Table of n, a(n) for n=0..1000
Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
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MATHEMATICA
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a[1] = 1; a[n_] := a[n] = 1 + Min[ 2a[Ceiling[(n - 1)/2]], 3a[Ceiling[(n - 1)/3]]]; Table[ a[n], {n, 72}] (from Robert G. Wilson v Jan 29 2005)
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CROSSREFS
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Cf. A002977.
Sequence in context: A058660 A059871 A076619 this_sequence A155689 A051263 A058674
Adjacent sequences: A007445 A007446 A007447 this_sequence A007449 A007450 A007451
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KEYWORD
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easy,nonn,nice
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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