%I #12 Feb 20 2021 23:10:31
%S 1,1,4,7,2,11,22,101,53,2,25,149,75,321,10,653,3110,907,5926,16829,
%T 2505,3174,13178,4323,5931,18033,20231,41698,155533,1323199,1477613,
%U 1133209,65051,109522,152567,610799,33521,8141,2386,156863,239559,1006091,113097,6353,11434
%N a(n) is the least integer k such that n/(Sum_{j=1..n} 1/phi(k*j)) is an integer.
%H Wikipedia, <a href="http://www.wikipedia.org/wiki/Harmonic_mean">Harmonic mean</a>.
%F a(n) <= A341810(n).
%o (PARI) a(n) = my(k=1); while (denominator(n/sum(j=1, n, 1/eulerphi(k*j))) != 1, k++); k; \\ _Michel Marcus_, Feb 20 2021
%Y Cf. A000010, A341810.
%K nonn
%O 1,3
%A _Seiichi Manyama_, Feb 20 2021