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Search: id:A065841
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| A065841 |
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a(1) = 1; a(2) = 2; a(3) = 3; a(n) is concatenation of a(n-3), a(n-2) and a(n-1). |
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2
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| 1, 2, 3, 123, 23123, 312323123, 12323123312323123, 2312331232312312323123312323123, 312323123123231233123231232312331232312312323123312323123
(list; graph; listen)
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OFFSET
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1,2
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REFERENCES
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C. A. Pickover, "Wonders of Numbers", Oxford University Press, 2001, chapter 122 '3 Weird Problems with 3 - Growth', pp. 272-274, 378.
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LINKS
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Harry J. Smith, Table of n, a(n) for n=1,...,13
C. A. Pickover, "Wonders of Numbers, Adventures in Mathematics, Mind and Meaning," Zentralblatt review
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PROGRAM
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(PARI) digitsIn(x)= { local(d); if (x==0, return(1)); d=1 + log(x)\log(10); if (10^d == x, d++, if (10^(d-1) > x, d--)); return(d) } Concat(a, b)= { return(a*10^digitsIn(b) + b) } { for (n = 1, 13, if (n>3, a=Concat(Concat(a3, a2), a1); a3=a2; a2=a1; a1=a, if (n==1, a=a3=1, if (n==2, a=a2=2, a=a1=3))); write("b065841.txt", n, " ", a) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Nov 01 2009]
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CROSSREFS
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Cf. A065842, A001590.
Sequence in context: A102697 A041813 A065842 this_sequence A051177 A125674 A095841
Adjacent sequences: A065838 A065839 A065840 this_sequence A065842 A065843 A065844
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KEYWORD
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nonn
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AUTHOR
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Patrick De Geest (pdg(AT)worldofnumbers.com), Nov 27 2001.
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EXTENSIONS
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OFFSET changed from 0,2 to 1,2 by Harry J. Smith (hjsmithh(AT)sbcglobal.net), Nov 01 2009
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