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Search: id:A006266
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| A006266 |
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A continued cotangent.
(Formerly M2073)
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+0
13
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| 2, 14, 2786, 21624372014, 10111847525912679844192131854786
(list; graph; listen)
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OFFSET
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1,1
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REFERENCES
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Shallit, Jeffrey; Predictable regular continued cotangent expansions. J. Res. Nat. Bur. Standards Sect. B 80B (1976), no. 2, 285-290.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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FORMULA
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Contribution from Artur Jasinski (grafix(AT)csl.pl), Sep 24 2008: (Start)
1) Recurrence: a(n+1)=a(n)^3 + 3*a(n) a(0)=2
2) Round[(1+Sqrt[2])^(3^n)] (End)
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MATHEMATICA
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Contribution from Artur Jasinski (grafix(AT)csl.pl), Sep 24 2008: (Start)
a = {}; k = 2; Do[AppendTo[a, k]; k = k^3 + 3 k, {n, 1, 10}]; a
or Table[Round[(1+Sqrt[2])^(3^n], {n, 0, 10}] (*Artur Jasinski*) (End)
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CROSSREFS
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A006267 [From Artur Jasinski (grafix(AT)csl.pl), Sep 24 2008]
Sequence in context: A032419 A130421 A156736 this_sequence A106484 A027739 A104773
Adjacent sequences: A006263 A006264 A006265 this_sequence A006267 A006268 A006269
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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