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a(n) = denominator of the continued fraction which has the positive divisors of n as its terms. The terms are written in order from 1 for the integer part, to n for the final term of the continued fraction.
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%I #13 Jan 19 2023 07:34:04

%S 1,2,3,9,5,44,7,74,28,112,11,2274,13,212,243,1193,17,7298,19,9627,465,

%T 508,23,445502,126,704,759,25797,29,1056347,31,38250,1125,1192,1265,

%U 13523875,37,1484,1563,3136897,41,3946112,43,98265,100092,2164,47

%N a(n) = denominator of the continued fraction which has the positive divisors of n as its terms. The terms are written in order from 1 for the integer part, to n for the final term of the continued fraction.

%e The divisors of 6 are 1,2,3,6. So a(6) is the denominator of 1 +1/(2 +1/(3 +1/6)) = 63/44.

%t f[n_] := Denominator[FromContinuedFraction[Divisors[n]]];Table[f[n], {n, 48}] (* _Ray Chandler_, Jan 22 2007 *)

%o (PARI) a(n) = contfracpnqn(divisors(n))[2,1]; \\ _Kevin Ryde_, Jan 19 2023

%Y Cf. A127611 (numerator), A127613.

%K frac,nonn

%O 1,2

%A _Leroy Quet_, Jan 19 2007

%E Extended by _Ray Chandler_, Jan 22 2007