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Search: id:A003064
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| A003064 |
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Smallest number with addition chain of length n. (Formerly M0667)
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+0 7
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| 1, 2, 3, 5, 7, 11, 19, 29, 47, 71, 127, 191, 379, 607, 1087, 1903, 3583, 6271, 11231, 18287, 34303, 65131, 110591, 196591, 357887, 685951, 1176431, 2211837, 4169527, 7624319, 14143037, 25450463, 46444543, 89209343, 155691199
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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M. Elia and F. Neri, A note on addition chains ..., pp. 166-181 of R. M. Capocelli, ed., Sequences, Springer-Verlag, NY 1990.
D. E. Knuth, The Art of Computer Programming. Addison-Wesley, Reading, MA, Vol. 2, p. 458; Vol. 2, 3rd. ed., p. 477.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
See A003313 for a much more extensive list of references and links.
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LINKS
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Daniel Bleichenbacher, Efficiency and Security of Cryptosystems based on Number Theory. PhD Thesis, Diss. ETH No. 11404, Zuerich 1996. See p. 60.
Achim Flammenkamp, Shortest addition chains
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EXAMPLE
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a(7) = 29 because 29 is the smallest number with a shortest addition chain requiring 7 additions. An example of a shortest addition chain for 29 is (1 2 3 4 7 11 18 29).
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CROSSREFS
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This is the "smallest inverse" of A003313. Cf. A003065.
Cf. A075530, A115617 [Smallest number for which Knuth's power tree method produces an addition chain of length n].
Sequence in context: A158069 A039726 A115617 this_sequence A057429 A065726 A118985
Adjacent sequences: A003061 A003062 A003063 this_sequence A003065 A003066 A003067
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KEYWORD
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nonn,nice,hard
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com) and D. E. Knuth
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EXTENSIONS
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New terms from Achim Flammenkamp, Math. Diplomarbeit, Univ. Bielefeld, 1991; and from Daniel Bleichenbacher (bleichen(AT)inf.ethz.ch)
a(25)-a(27) from the 3rd. ed. of Knuth vol. 2, sent by David Moulton, Jun 24, 2003.
a(28)-a(30) from the Flammenkamp web site, Feb 01 2005
a(31)=25450463 computed Dec 15 2005 by N. Clift (neillclift(AT)msn.com). - Hugo Pfoertner (hugo(AT)pfoertner.org), Jan 29 2006
a(32)=46444543 computed by N. Clift (neillclift(AT)msn.com), Jun 15 2007
89209343 and 155691199 from N. Clift (neillclift(AT)msn.com), May 21 2008
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