%I
%S 0,1,2,3,1,5,2,4,3,5,2,8,1,7,5,7,3,10,4,9,6,10,3,13,6,8,7,11,5,19,6,9,
%T 7,9,6,18,5,13,9,16,5,22,7,16,13,12,9,19,7,16,11,15,8,21,12,16,14,14,
%U 6,33,8,18,14,15,10,27,10,21,13,29,10,29,3,18,19
%N Number of 1<=i<n such that i*n1 is prime.
%e For n=2, i=2 gives a prime (3), so a(2)=1.
%e For n=10, i=2,3,6,8,9 give primes, so a(10)=5.
%o (PARI) nphi(n)=local(c); c=0; for (i=1,n1,if (isprime(i*n1),c++)); c for(i=1,60,print1(","nphi(i)))
%o (PARI) a(n) = sum(i=1, n, isprime(i*n1)); \\ _Michel Marcus_, Mar 17 2014
%K nonn
%O 1,3
%A _Jon Perry_, Jul 28 2003
%E a(2) corrected and more terms from _Michel Marcus_, Mar 17 2014
