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%I #13 Jan 14 2020 22:19:09
%S 1,8,27,108,180,396,672,1056,1372,1760,2352,3087,3696,3744,4896,5733,
%T 7497,9724,11907,13600,15200,18513,19773,23940,24752,28917,32319,
%U 33534,42282,45472,47500,52668,55890,59976,66048,74240,77792,81144,86944,100035,105248,109368,122825,127908,134368,144648,156325,168948,175770
%N a(n) is the index of the first occurrence of n in A331284.
%C Also positions of records in A331284.
%C a(n) is the least k such that in range 1 .. k of A329605 (equally: in A329606[1..k]) there can be found exactly n occurrences of some term. In A329605 these "champion terms" are A329605(a(n)): 1, 4, 16, 24, 48, 192, 96, 192, 384, 288, 288, 576, 576, 576, 1152, 2304, 4608, 9216, 576, 2304, ..., that appear all to be 3-smooth numbers (in A003586).
%C For example, a(5)=180 and 48 is the first term in A329605 to occur for five times, as A329605(22) = A329605(42) = A329605(75) = A329605(112) = A329605(180) = 48.
%F A331284(a(n)) = n for all n >= 1.
%Y Cf. A331284 (a left inverse).
%Y Cf. A003586, A329605, A329606.
%K nonn
%O 1,2
%A _Antti Karttunen_, Jan 14 2020