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A127616 a(n) = denominator of the continued fraction which has the positive integers which are <= n and are coprime to n as its terms. The terms are written in order from n-1 for the integer part, to 1 for the final term of the continued fraction. 2
1, 1, 1, 1, 10, 1, 225, 21, 489, 29, 740785, 43, 83120346, 2144, 111382, 200683, 2789144166880, 6270, 764582487395121, 658073, 4282119239, 88713109, 111056404320064218961, 2040581, 3557587238290412640, 36510389904 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

Table of n, a(n) for n=1..26.

EXAMPLE

The positive integers coprime to 8 and <= 8 are 1,3,5,7. So a(8) is the denominator of 7 +1/(5 +1/(3 +1/1)) = 151/21.

MATHEMATICA

f[n_] := Select[Range[n], GCD[ #, n] == 1 &]; g[n_] := Denominator[FromContinuedFraction[Reverse[f[n]]]]; Table[g[n], {n, 27}] (* Ray Chandler, Jan 22 2007 *)

CROSSREFS

Cf. A127614, A127615.

Sequence in context: A223512 A131367 A048176 * A191549 A285647 A287975

Adjacent sequences:  A127613 A127614 A127615 * A127617 A127618 A127619

KEYWORD

frac,nonn

AUTHOR

Leroy Quet, Jan 19 2007

EXTENSIONS

Extended by Ray Chandler, Jan 22 2007

STATUS

approved

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Last modified October 25 01:40 EDT 2021. Contains 348233 sequences. (Running on oeis4.)