A219027 Number of non-primitive roots for n, less than n.

0, 0, 1, 2, 2, 4, 4, 7, 6, 7, 6, 11, 8, 11, 14, 15, 8, 15, 12, 19, 20, 17, 12, 23, 16, 21, 20, 27, 16, 29, 22, 31, 32, 25, 34, 35, 24, 31, 38, 39, 24, 41, 30, 43, 44, 35, 24, 47, 36, 41, 50, 51, 28, 47, 54, 55, 56, 45, 30, 59, 44, 53, 62, 63, 64, 65, 46, 67, 68

Offset

1,4

Comments

a(n) will be the same as A219029(n) except when n is a member of A033949 or n = 1, i.e. n is not 2, 4, prime, power of a prime, twice a prime, or twice a prime power. In such cases, when n is a member of A033949, then a(n) = n-1.

Links

Table of n, a(n) for n=1..69.

Formula

n-1-A046144(n).

Prog

(PARI) for(i=1, 100, p=0; for(q=1, i-1, if(gcd(q, i)>1||znorder(Mod(q, i))!=eulerphi(i), p++)); print1(p", "))

Crossrefs

Cf. A008330 (number of primitive roots for the n-th prime, less than n-th prime).

Cf. A046144 (number of primitive roots for n, less than n).

Cf. A010554 (value of phi(phi(n))).

Cf. A219029.

Sequence in context: A059886 A272339 A267261 * A341949 A338333 A287144

Adjacent sequences: A219024 A219025 A219026 * A219028 A219029 A219030

Keyword

nonn

Author

V. Raman, Nov 10 2012

Status

approved