%I #9 Apr 18 2020 19:45:41
%S 0,1,0,1,0,0,0,1,-1,1,0,0,0,0,0,1,0,-1,0,1,-1,1,0,0,0,0,-1,1,0,0,0,1,
%T -1,1,-1,0,0,0,0,1,0,-1,0,1,-1,1,0,0,-1,1,0,0,0,-1,1,0,-1,1,0,0,0,0,
%U -1,2,-1,0,0,1,-1,0,0,0,0,0,0,0,0,0,0,1,-2,2,0,-1,1,-1,0,1,0,-1,0,1,-1,1,-1,1,0,-1,0,1,0,0,0,0,-1
%N a(1) = 0, then after the first differences of A064415.
%H Antti Karttunen, <a href="/A334195/b334195.txt">Table of n, a(n) for n = 1..65537</a>
%F a(1) = 0; and for n > 1, a(n) = A064415(n) - A064415(n-1).
%F a(n) = A334090(n) - A334091(n).
%o (PARI)
%o A003434(n) = for(k=0, n, n>1 || return(k); n=eulerphi(n));
%o A064415(n) = if(1==n,0, A003434(n)-(n%2));
%o A334195(n) = if(1==n,0,A064415(n)-A064415(n-1));
%Y Cf. A003434, A064415, A334090, A334091, A334196.
%Y Also, from a(3) onward the first differences of A054725.
%K sign
%O 1,64
%A _Antti Karttunen_, Apr 18 2020