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A130669 Smallest k such that phi(x) = k has exactly n odd solutions. 2

%I

%S 1,6,24,60,144,72,216,480,600,240,432,1152,1296,1080,4608,2016,720,

%T 2520,2400,1440,5184,4032,2880,5280,7776,2160,5760,21840,7560,9600,

%U 6720,16560,5040,15552,6480,13440,10800,11520,20736,4320,18144,12096,28512,16800

%N Smallest k such that phi(x) = k has exactly n odd solutions.

%H Vladeta Jovovic and Donovan Johnson, <a href="/A130669/b130669.txt">Table of n, a(n) for n = 1..1000</a> (first 100 terms from Vladeta Jovovic)

%e a(3) = 24 because there are 3 odd solutions (35, 39, 45) to phi(x) = 24 and for every k < 24 the number of odd solutions to phi(x) = k is unequal to 3.

%Y Cf. A007374, A130670.

%K nonn

%O 1,2

%A _Franz Vrabec_, Jun 27 2007

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Last modified January 28 16:02 EST 2023. Contains 359895 sequences. (Running on oeis4.)