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%I #7 Aug 18 2015 00:21:44
%S 1,1,1,2,1,4,2,5,5,2,4,6,3,11,11,14,4,6,8,8,7,20,18,11,16,10,26,12,21,
%T 10,18,30,14,35,11,15,18,41,41,44,13,27,21,36,18,11,23,56,23,54,39,17,
%U 40,64,65,65,19,28,33,30,71,30,46,30,77,19,27,86,36,73
%N Let p = n-th odd prime; a(n) = number of primitive roots of p which might be expected to be relatively prime to p-1, that is, a(n) = phi(p-1)^2/(p-1) rounded to the nearest integer.
%D R. Osborn, Tables of All Primitive Roots of Odd Primes Less Than 1000, Univ. Texas Press, Austin, TX, 1961, pp. 69-70.
%p A128861 := proc(n) local p ; p := ithprime(n+1) ; round( (numtheory[phi](p-1))^2 / (p-1) ) ; end: seq(A128861(n),n=1..70) ; # _R. J. Mathar_, Oct 31 2007
%K nonn,easy
%O 1,4
%A _N. J. A. Sloane_, Apr 20 2007
%E More terms from _R. J. Mathar_, Oct 31 2007
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