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A212490 Least number m > 1 such that A000203(x)*x = m has exactly n solutions. 3

%I

%S 6,336,333312,5418319872,1584858562560

%N Least number m > 1 such that A000203(x)*x = m has exactly n solutions.

%C 6 = 6.

%C 336 = 6*28*2.

%C 333312 = 6*28*496*2*2.

%C 5418319872 = 6*28*496*8128*2*2*2.

%D R. K. Guy, Unsolved Problems in Theory of Numbers, Springer-Verlag, Third Edition, 2004, B11.

%e For n=3, 333312 has exactly 3 solutions: sigma(434)*434 = 333312, sigma(372)*372 = 333312, and sigma(336)*336 = 333312; therefore a(3) = 333312.

%Y Cf. A212489, A212327, A212373.

%K nonn,more

%O 1,1

%A _Naohiro Nomoto_, May 18 2012

%E a(5) from _Donovan Johnson_, May 20 2012

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Last modified June 2 18:17 EDT 2020. Contains 334787 sequences. (Running on oeis4.)