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A219027 Number of non-primitive roots for n, less than n. 4
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 (list; graph; refs; listen; history; text; internal format)
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 * A287144 A085893 A230167

Adjacent sequences:  A219024 A219025 A219026 * A219028 A219029 A219030

KEYWORD

nonn

AUTHOR

V. Raman, Nov 10 2012

STATUS

approved

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Last modified February 24 10:37 EST 2020. Contains 332209 sequences. (Running on oeis4.)