A318830 - OEIS

%I #6 Sep 10 2018 06:10:56

%S 0,0,0,1,0,1,0,3,4,3,0,3,0,5,6,7,0,5,0,7,8,9,0,7,16,11,16,9,0,7,0,15,

%T 16,15,22,11,0,17,22,15,0,11,0,19,20,21,0,15,36,19,30,21,0,17,38,23,

%U 32,27,0,15,0,29,34,31,32,15,0,31,40,21,0,23,0,35,38,33,56,23,0,31,52,39,0,23,60,41,54,39,0,23,54,43

%N a(n) = phi(n) - gcd(phi(n), n-1).

%H Antti Karttunen, <a href="/A318830/b318830.txt">Table of n, a(n) for n = 1..65537</a>

%F a(n) = A000010(n) - A049559(n) = phi(n) - gcd(phi(n), n-1).

%F a(n) = A318827(n) - A051953(n).

%o (PARI)

%o A049559(n) = gcd(eulerphi(n), n-1); \\ From A049559.

%o A318830(n) = (eulerphi(n)-A049559(n));

%Y Cf. A000010, A049558, A051953, A318827.

%K nonn

%O 1,8

%A _Antti Karttunen_, Sep 09 2018