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A128859 Let p = n-th odd prime; a(n) = number of primitive roots of p which are <= (p-1)/2. 1
0, 1, 1, 1, 2, 4, 2, 4, 6, 4, 6, 8, 6, 9, 12, 10, 8, 10, 9, 12, 10, 16, 20, 16, 20, 13, 22, 18, 24, 17, 18, 32, 18, 36, 16, 24, 26, 36, 42, 37, 24, 29, 32, 42, 23, 16, 38, 49, 36, 56, 44, 32, 44, 64, 59, 66, 33, 44, 48, 40, 72, 48, 55, 48, 78, 35, 48, 79, 56, 80, 80, 60, 60, 55 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

REFERENCES

R. Osborn, Tables of All Primitive Roots of Odd Primes Less Than 1000, Univ. Texas Press, Austin, TX, 1961, pp. 69-70.

LINKS

Table of n, a(n) for n=1..74.

CROSSREFS

Cf. A118818.

Sequence in context: A236186 A143271 A267654 * A047975 A112791 A227346

Adjacent sequences:  A128856 A128857 A128858 * A128860 A128861 A128862

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Apr 20 2007

EXTENSIONS

More terms from Don Reble, Apr 20 2007

STATUS

approved

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Last modified February 24 01:16 EST 2020. Contains 332195 sequences. (Running on oeis4.)