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 A216322 Number of primitive roots Modd n (see A216321). 1
 1, 1, 1, 1, 1, 2, 2, 2, 2, 4, 0, 2, 2, 2, 4, 4, 2, 6, 0, 2, 4, 10, 0, 4, 4, 6, 0, 6, 0, 8, 8, 4, 8, 4, 0, 6, 6, 4, 0, 8, 0, 12, 8, 4, 10, 22, 8, 12, 8, 8, 8, 12, 6, 8, 8, 6, 12, 28, 8, 8, 8, 6, 16, 8, 8, 20, 16, 10, 8, 24, 8, 12, 12, 8, 12, 8, 8, 24, 16, 18, 16, 40, 8, 16, 12 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,6 COMMENTS This sequence coincides with A216321 for all n values from A206551 (cyclic multiplicative Modd n group) and the entry is 0 otherwise (if no primitive root exists, that is, n is from the complementary sequence A206552). LINKS FORMULA a(n) = A216321(n) if n belongs to the sequence A206551 and a(n)=0 if n belongs to A206552. EXAMPLE a(8) = phi(phi(2*8)/2) = 2 , with phi = A000010, because 8 = A206551(8). a(12) = 0 because 12 = A206552(1). CROSSREFS Cf. A216321, A046144 (modulo n analog). Sequence in context: A078228 A119762 A153667 * A335383 A125914 A086668 Adjacent sequences:  A216319 A216320 A216321 * A216323 A216324 A216325 KEYWORD nonn AUTHOR Wolfdieter Lang, Sep 21 2012 STATUS approved

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Last modified August 14 07:04 EDT 2020. Contains 336477 sequences. (Running on oeis4.)