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A061708 Smallest number whose square has (2n - 1)^2 divisors. 0

%I

%S 1,6,36,216,210,7776,46656,1260,1679616,10077696,7560,362797056,44100,

%T 18480,78364164096,470184984576,272160,264600,101559956668416,1632960,

%U 3656158440062976,21936950640377856,180180,789730223053602816,9261000

%N Smallest number whose square has (2n - 1)^2 divisors.

%C a(n) <= 6^(n-1); 36^(n-1) has (2n-1)^2 divisors for all n.

%F a(n) = Min_{x : d(x^2) = (2n-1)^2};

%F a(n) = Min_{x : A000005(A000290(x)) = A000290(A005408(n))}

%e n = 8, a(8) = 1260 = 2*2*3*3*5*7 and d(1260^2) = d(2*2*2*2*3*3*3*3*5*5*7*7) = 225 = (2*8-1)^2.

%e n = 14, a(14) = 18480 and d((2*2*2*2*2*2*2*2*3*5*7*11)^2) = 729 = (2*14-1)^2.

%Y Cf. A000005, A000290, A005179, A005408, A016017, A025281, A048691.

%K nonn

%O 1,2

%A _Labos Elemer_, Jun 19 2001

%E More terms from _David Wasserman_, Jun 24 2002

%E Edited by _Charlie Neder_, Jun 03 2019

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Last modified November 17 06:06 EST 2019. Contains 329217 sequences. (Running on oeis4.)