

A128860


Let p = nth odd prime; a(n) = number of primitive roots of p which are relatively prime to p1.


1



0, 1, 1, 1, 2, 4, 1, 6, 5, 3, 5, 6, 3, 13, 11, 10, 5, 5, 10, 8, 9, 16, 19, 11, 16, 10, 22, 13, 23, 12, 15, 30, 9, 35, 8, 17, 15, 46, 41, 37, 14, 34, 20, 36, 16, 10, 21, 49, 26, 54, 43, 17, 38, 64, 71, 65, 23, 32, 33, 22, 71, 30, 56, 28, 77, 16, 26, 79, 38, 74
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OFFSET

1,5


COMMENTS

The number of primitive roots without the restriction of relativeprimality is in A008330, so a(n)<=A008330(n+1). A table of prime moduli is in A128250.  R. J. Mathar, Oct 31 2007


REFERENCES

R. Osborn, Tables of All Primitive Roots of Odd Primes Less Than 1000, Univ. Texas Press, Austin, TX, 1961, pp. 6970.


LINKS

T. D. Noe, Table of n, a(n) for n=1..1000


MAPLE

A128250 := proc(g, p) local k ; if gcd(g, p) > 1 then RETURN(0) ; fi ; for k from 1 do if (g^k mod p ) = 1 then RETURN(k) ; fi ; od: end: proots := proc(p) local a, g ; a := 0 ; for g from 1 to p do if A128250(g, p) = p1 and gcd(g, p1) = 1 then a := a+1 ; fi ; od: RETURN(a) ; end: A128860 := proc(n) local p; p := ithprime(n+1) ; proots(p) ; end: seq(A128860(n), n=1..60) ; # R. J. Mathar, Oct 31 2007


CROSSREFS

Sequence in context: A066248 A065164 A138124 * A019680 A249144 A080032
Adjacent sequences: A128857 A128858 A128859 * A128861 A128862 A128863


KEYWORD

nonn,easy


AUTHOR

N. J. A. Sloane, Apr 20 2007


EXTENSIONS

More terms from R. J. Mathar, Oct 31 2007


STATUS

approved



