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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 (list; graph; refs; listen; history; text; internal format)
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: A247891 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

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Last modified August 23 00:58 EDT 2019. Contains 326211 sequences. (Running on oeis4.)