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A006269 A continued cotangent.
(Formerly M4028)
11
5, 140, 2744420, 20670535451567121260, 8831921094058107711185956797335984862612406515067837739780 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

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).

LINKS

Table of n, a(n) for n=0..4.

FORMULA

Contribution from Artur Jasinski, Oct 03 2008: (Start)

Recurrence: a(n+1)=a(n)^3+3*a(n) and a(0)=5

or

a(n)=Table[Round[(5/2 + Sqrt[29]/2)^(3^(n - 1))], {n, 1, 8}] (*Artur Jasinski*) (End)

MATHEMATICA

Contribution from Artur Jasinski, Oct 03 2008: (Start)

a = {}; k = 5; Do[AppendTo[a, k]; k = k^3 + 3 k, {n, 1, 8}]; a

or

Table[Round[(5/2 + Sqrt[29]/2)^(3^(n - 1))], {n, 1, 8}] (*Artur Jasinski*) (End)

NestList[#^3+3#&, 5, 5] (* Harvey P. Dale, Feb 14 2013 *)

CROSSREFS

Sequence in context: A193756 A136464 A203523 * A066264 A171776 A277401

Adjacent sequences:  A006266 A006267 A006268 * A006270 A006271 A006272

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified April 18 12:34 EDT 2019. Contains 322209 sequences. (Running on oeis4.)