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Search: id:A006268
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| A006268 |
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A continued cotangent.
(Formerly M3141)
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+0
12
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| 3, 36, 46764, 102266868132036, 1069559300034650646049671039050649693658764, 12235299511782582501718737703928003159270074844240197923140389005995265963422454\ 41950466608853108106356422588162773879214824036
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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a(6)=1223529951178258250171873770392800315927007484424019792314038900\
599526596342245441950466608853108106356422588162773879214824036 Artur Jasinski (grafix(AT)csl.pl), Oct 03 2008
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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).
Shallit, Jeffrey; Predictable regular continued cotangent expansions. J. Res. Nat. Bur. Standards Sect. B 80B (1976), no. 2, 285-290.
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FORMULA
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Recurence: a(n+1)=a(n)^3+3a(n) and a(0)=3 a(n)=Round[(3/2 + Sqrt[13]/2)^(3^(n - 1))] [From Artur Jasinski (grafix(AT)csl.pl), Oct 03 2008]
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MATHEMATICA
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Contribution from Artur Jasinski (grafix(AT)csl.pl), Oct 03 2008: (Start)
a = {}; k = 3; Do[AppendTo[a, k]; k = k^3 + 3 k, {n, 1, 6}]; a
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Table[Round[N[(3/2 + Sqrt[13]/2)^(3^(n - 1)), 1000]], {n, 1, 8}] (*Artur Jasinski*) (End)
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CROSSREFS
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Sequence in context: A163966 A088322 A080807 this_sequence A073236 A002563 A140448
Adjacent sequences: A006265 A006266 A006267 this_sequence A006269 A006270 A006271
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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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