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%I #6 Oct 07 2021 02:16:04
%S 1,3,9,15,81,45,729,105,225,405,59049,495,531441,3645,2025,1155,
%T 43046721,3675,387420489,4455,18225,295245,31381059609,8085,50625,
%U 2657205,65025,40095,22876792454961,34425,205891132094649,19635,1476225,215233605,455625,62475
%N a(n) is the least term of A326835 whose number of divisors is n.
%C First differs from A038547 at n = 12.
%C All the terms are odd since all the terms of A326835 are odd (as phi(1) = phi(2) = 1).
%C a(n) exists for any n since 3^(n-1) is a term of A326835 which has n divisors.
%F a(n) <= 3^(n-1), with equality if n is prime.
%F a(n) >= A038547(n).
%t seq[m_] := Module[{p = Select[Range[m], PrimeQ], s = Table[0, {m}], c, nd, ndd}, s[[p]] = 3^(p - 1); c = Length[p]; n = 1; While[c < m, nd = DivisorSigma[0, n]; If[nd <= m && s[[nd]] == 0, ndd = Length@Union[EulerPhi /@ Divisors[n]]; If[ndd == nd, c++; s[[nd]] = n]]; n++]; s]; seq[30]
%Y Cf. A038547, A326835, A328858, A348198.
%K nonn
%O 1,2
%A _Amiram Eldar_, Oct 06 2021
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