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A065841 a(1) = 1; a(2) = 2; a(3) = 3; a(n) is concatenation of a(n-3), a(n-2) and a(n-1). 2
1, 2, 3, 123, 23123, 312323123, 12323123312323123, 2312331232312312323123312323123, 312323123123231233123231232312331232312312323123312323123 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

REFERENCES

C. A. Pickover, "Wonders of Numbers", Oxford University Press, 2001, chapter 122 '3 Weird Problems with 3 - Growth', pp. 272-274, 378.

LINKS

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

PROG

(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]

CROSSREFS

Cf. A065842, A001590.

Sequence in context: A102697 A041813 A065842 * A051177 A125674 A180533

Adjacent sequences:  A065838 A065839 A065840 * A065842 A065843 A065844

KEYWORD

nonn,base,easy

AUTHOR

Patrick De Geest (pdg(AT)worldofnumbers.com), Nov 27 2001.

EXTENSIONS

OFFSET changed from 0,2 to 1,2 by Harry J. Smith (hjsmithh(AT)sbcglobal.net), Nov 01 2009

Edited by Charles R Greathouse IV (charles.greathouse(AT)case.edu), Apr 27 2010

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Last modified February 15 19:07 EST 2012. Contains 205852 sequences.