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A255367
a(n) = r^(p-2) mod p, where p is the n-th prime and r is the least positive primitive root of p.
2
1, 2, 3, 5, 6, 7, 6, 10, 14, 15, 21, 19, 7, 29, 19, 27, 30, 31, 34, 61, 44, 53, 42, 30, 39, 51, 62, 54, 91, 38, 85, 66, 46, 70, 75, 126, 63, 82, 67, 87, 90, 91, 181, 116, 99, 133, 106, 149, 114, 191, 78, 205, 69, 42, 86, 158, 135, 226, 111, 94, 189, 147, 123
OFFSET
1,2
COMMENTS
a(n) is the last element of row n of A254309.
LINKS
FORMULA
a(n) = r^(p-2) mod p, with p = A000040(n) and r = A001918(n).
MAPLE
a:= n-> (p-> numtheory[primroot](p)&^(p-2) mod p)(ithprime(n)):
seq(a(n), n=1..70);
MATHEMATICA
a[n_] := With[{p = Prime[n]}, Mod[PrimitiveRoot[p]^(p-2), p]]; Array[a, 70] (* Jean-François Alcover, Mar 24 2017 *)
CROSSREFS
KEYWORD
nonn,look
AUTHOR
Alois P. Heinz, May 04 2015
STATUS
approved