

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 n1 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
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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



