%N Odd n such that there exists an even number k < n with phi(k) = phi(n).
%C These numbers m appear to satisfy cototient[m] > totient[m] or 2phi[m] < m; - they seem to be the missing terms mentioned in A067800. - _Labos Elemer_, May 08 2003
%C All elements in this sequence must have 2*phi(n) < n, but not the reverse. See A118700. - _Franklin T. Adams-Watters_, May 21 2006
%H Robert Israel, <a href="/A036798/b036798.txt">Table of n, a(n) for n = 1..10000</a>
%p N:= 10^4: # to get all terms <= N
%p PhiE:= map(numtheory:-phi, [seq(i,i=2..N,2)]):
%p A:= NULL:
%p for n from 1 to N by 2 do
%p t:= numtheory:-phi(n);
%p if 2*t < n and member(t, PhiE[1..(n-1)/2]) then A:= A,n fi;
%p A; # _Robert Israel_, Jan 06 2017
%t Select[ Range[1, 4483, 2], Mod[ #, EulerPhi[ # ]] != # - EulerPhi[ # ] &] (* _Robert G. Wilson v_, Jan 10 2004 *)
%Y Cf. A000010, A067800, A083254.
%Y Cf. A091495 (Odd, squarefree n such that n/phi(n) > 2).
%Y Cf A118700, A119434.
%A _David W. Wilson_