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%I #9 Oct 10 2019 11:32:09
%S 1,1,1,1,10,1,225,21,489,29,740785,43,83120346,2144,111382,200683,
%T 2789144166880,6270,764582487395121,658073,4282119239,88713109,
%U 111056404320064218961,2040581,3557587238290412640,36510389904
%N 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.
%e 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.
%t 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 *)
%Y Cf. A127614, A127615.
%K frac,nonn
%O 1,5
%A _Leroy Quet_, Jan 19 2007
%E Extended by _Ray Chandler_, Jan 22 2007