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A349498 a(n) is the least number k such that A349497(k) = n, or -1 if no such k exists.

%I A349498 #5 Nov 20 2021 20:49:18
%S A349498 1,6,24,170,140,270,1140,630,1400,4420,2016,8680,11704,18620,8190,
%T A349498 20196,12960,90860,13860,30800,55860,148770,51408,30240,78120,242060,
%U A349498 153120,282555,65520,564564,268128,381150,798560,592515,535680,1503216,318240,664020,726180,790020
%N A349498 a(n) is the least number k such that A349497(k) = n, or -1 if no such k exists.
%e A349498 The elements of the continued fractions of the harmonic mean of the divisors of the first 10 terms are:
%e A349498    n  a(n)  elements
%e A349498   --  ----  --------
%e A349498    1     1  1
%e A349498    2     6  2
%e A349498    3    24  3,5
%e A349498    4   170  4,5,16
%e A349498    5   140  5
%e A349498    6   270  6
%e A349498    7  1140  8,7
%e A349498    8   630  8,13
%e A349498    9  1400  9,31
%e A349498   10  4420  10,44,10
%t A349498 f[n_] := Min[ContinuedFraction[DivisorSigma[0, n] / DivisorSigma[-1, n]]]; seq[len_, nmax_] := Module[{s = Table[0, {len}], c = 0, n = 1, i}, While[c < len && n < nmax, i = f[n]; If[i <= len && s[[i]] == 0, c++; s[[i]] = n]; n++]; s]; seq[25, 10^6]
%Y A349498 Cf. A099377, A099378, A349473, A349497.
%K A349498 nonn
%O A349498 1,2
%A A349498 _Amiram Eldar_, Nov 20 2021