%I A032446
%S A032446 3,4,4,5,2,6,0,6,4,5,2,10,0,2,2,7,0,8,0,9,4,3,2,11,0,2,2,3,2,9,
%T A032446 0,8,2,0,2,17,0,0,2,10,2,6,0,6,0,3,0,17,0,4,2,3,2,9,2,6,0,3,0,17,
%U A032446 0,0,2,9,2,7,0,2,2,3,0,21,0,2,2,0,0,7,0,12,4,3,2,12,0,2,0,8,2,10
%N A032446 Number of solutions to phi(k)=2n.
%D A032446 Albert H. Beiler, "Recreations in the Theory of Numbers, The Queen of 
               Mathematics Entertains, " Second Edition, Dover Publications, Inc., 
               NY, 1966, page 90.
%D A032446 Carl Pomerance, Popular values of Euler's function.Mathematica 27 (1980), 
               84-89.
%H A032446 T. D. Noe, <a href="b032446.txt">Table of n, a(n) for n=1..5000</a>
%e A032446 If n=8 then phi(x)=2*8=16 is satisfied for only a(8)=6 values of x, viz. 
               17, 32, 34, 40, 48, 60.
%p A032446 with(numtheory); [ seq(nops(invphi(2*n)), n=1..90) ];
%t A032446 t = Table[0, {100} ]; Do[a = EulerPhi[n]; If[a < 202, t[[a/2]]++ ], {n, 
               3, 10^5} ]; t
%Y A032446 Bisection of A014197.
%Y A032446 Cf. A000010 and A005277.
%Y A032446 Cf. A085758.
%Y A032446 Sequence in context: A058559 A112180 A158012 this_sequence A028949 A107574 
               A053405
%Y A032446 Adjacent sequences: A032443 A032444 A032445 this_sequence A032447 A032448 
               A032449
%K A032446 nonn,easy,nice
%O A032446 1,1
%A A032446 Ursula Gagelmann (gagelmann(AT)altavista.net)
%E A032446 Extended by Robin Trew (trew(AT)hcs.harvard.edu).