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Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Index entries for primes by primitive root
pr=20; Select[Prime[Range], MultiplicativeOrder[pr, # ] == #-1 &]
Sequence in context: A040123 A038883 A141188 * A184777 A045433 A216535
Adjacent sequences: A019344 A019345 A019346 * A019348 A019349 A019350
David W. Wilson