%I A007374 M1093
%S A007374 1,2,4,8,12,32,36,40,24,48,160,396,2268,704,312,72,336,216,936,144,624,
%T A007374 1056,1760,360,2560,384,288,1320,3696,240,768,9000,432,7128,4200,480,
%U A007374 576,1296,1200,15936,3312,3072,3240,864,3120,7344,3888,720,1680,4992
%N A007374 Smallest k such that phi(x) = k has exactly n solutions.
%C A007374 Carmichael conjectured that no term exists for n=1.
%D A007374 M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, 
               National Bureau of Standards Applied Math. Series 55, 1964 (and various 
               reprintings), p. 840.
%D A007374 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%H A007374 T. D. Noe, <a href="b007374.txt">Table of n, a(n) for n = 2..778</a>
%H A007374 M. Abramowitz and I. A. Stegun, eds., <a href="http://www.nrbook.com/
               abramowitz_and_stegun/">Handbook of Mathematical Functions</a>, National 
               Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 
               [alternative scanned copy].
%H A007374 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               TotientValenceFunction.html">Phi function.</a>
%H A007374 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               CarmichaelsTotientFunctionConjecture.html">Carmichael's Totient Function 
               Conjecture</a>.
%t A007374 a = Table[ 0, {10^5} ]; Do[ s = EulerPhi[ n ]; If[ s < 100001, a[ [ s 
               ] ]++ ], {n, 1, 10^6} ]; Do[ k = 1; While[ a[ [ k ] ] != n, k++ ]; 
               Print[ k ], {n, 2, 75} ]
%Y A007374 Cf. A000010. Essentially same as A014573. Records in A105207, A105208. 
               See also A097942.
%Y A007374 Cf. A105207, A105208.
%Y A007374 Sequence in context: A082906 A085083 A076745 this_sequence A105207 A133802 
               A076202
%Y A007374 Adjacent sequences: A007371 A007372 A007373 this_sequence A007375 A007376 
               A007377
%K A007374 nonn,easy,nice
%O A007374 2,2
%A A007374 N. J. A. Sloane (njas(AT)research.att.com), Mira Bernstein, Robert G. 
               Wilson v (rgwv(AT)rgwv.com)
%E A007374 Link fixed by Charles R Greathouse IV (charles.greathouse(AT)case.edu), 
               Oct 06 2009