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A041019 Denominators of continued fraction convergents to sqrt(13). 10
1, 1, 2, 3, 5, 33, 38, 71, 109, 180, 1189, 1369, 2558, 3927, 6485, 42837, 49322, 92159, 141481, 233640, 1543321, 1776961, 3320282, 5097243, 8417525, 55602393, 64019918, 119622311, 183642229, 303264540 (list; graph; refs; listen; history; internal format)
OFFSET

0,3

COMMENTS

Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), Jun 12 2010: (Start)

The a(n) terms of this sequence can be constructed with the terms of sequence A006190.

For the terms of the periodical sequence of the continued fraction for sqrt(13) see A010122. We observe that its period is five. The decimal expansion of sqrt(13) is A010470.

(End)

FORMULA

Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), Jun 12 2010: (Start)

a(5*n) = A006190(3*n+1), a(5*n+1) = (A006190(3*n+2) - A006190(3*n+1))/2, a(5*n+2) = (A006190(3*n+2) + A006190(3*n+1))/2, a(5*n+3) = A006190(3*n+2) and a(5*n+4) = A006190(3*n+3)/2.

(End)

MATHEMATICA

Table[Denominator[FromContinuedFraction[ContinuedFraction[Sqrt[13], n]]], {n, 1, 50}] (*From Vladimir Joseph Stephan Orlovsky, Mar 16 2011*)

CROSSREFS

Cf. A041018.

Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), Jun 12 2010: (Start)

Cf. A041019, A041047, A041091, A041151, A041227, A041319, A041427 and A041551.

(End)

Sequence in context: A036797 A163079 A109845 * A041977 A089213 A029499

Adjacent sequences:  A041016 A041017 A041018 * A041020 A041021 A041022

KEYWORD

nonn,cofr,easy

AUTHOR

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

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Last modified February 17 13:28 EST 2012. Contains 206031 sequences.