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A006266 A continued cotangent.
(Formerly M2073)
12
2, 14, 2786, 21624372014, 10111847525912679844192131854786 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

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).

FORMULA

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)

MATHEMATICA

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)

CROSSREFS

A006267 [From Artur Jasinski (grafix(AT)csl.pl), Sep 24 2008]

Sequence in context: A190634 A130421 A156736 * A106484 A027739 A193307

Adjacent sequences:  A006263 A006264 A006265 * A006267 A006268 A006269

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

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Last modified February 17 06:27 EST 2012. Contains 205998 sequences.