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.

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

Alois P. Heinz, Table of n, a(n) for n = 1..10000

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

Cf. A000040, A001918, A254309.

Sequence in context: A354370 A113821 A319523 * A280098 A019517 A031976

Adjacent sequences: A255364 A255365 A255366 * A255368 A255369 A255370

Keyword

nonn,look

Author

Alois P. Heinz, May 04 2015

Status

approved