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A006268
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A continued cotangent.
(Formerly M3141)
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11
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3, 36, 46764, 102266868132036, 1069559300034650646049671039050649693658764, 1223529951178258250171873770392800315927007484424019792314038900599526596342245441950466608853108106356422588162773879214824036
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| a(6)=1223529951178258250171873770392800315927007484424019792314038900\
599526596342245441950466608853108106356422588162773879214824036 Artur Jasinski (grafix(AT)csl.pl), Oct 03 2008
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REFERENCES
| 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
| Recurrence: 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
| 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
or
Table[Round[N[(3/2 + Sqrt[13]/2)^(3^(n - 1)), 1000]], {n, 1, 8}] (*Artur Jasinski*) (End)
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CROSSREFS
| Sequence in context: A163966 A088322 A080807 * A073236 A002563 A140448
Adjacent sequences: A006265 A006266 A006267 * A006269 A006270 A006271
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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