cp's OEIS Frontend

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.

%I A255367 #16 Mar 24 2017 09:24:05
%S A255367 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,
%T A255367 51,62,54,91,38,85,66,46,70,75,126,63,82,67,87,90,91,181,116,99,133,
%U A255367 106,149,114,191,78,205,69,42,86,158,135,226,111,94,189,147,123
%N 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.
%C A255367 a(n) is the last element of row n of A254309.
%H A255367 Alois P. Heinz, <a href="/A255367/b255367.txt">Table of n, a(n) for n = 1..10000</a>
%F A255367 a(n) = r^(p-2) mod p, with p = A000040(n) and r = A001918(n).
%p A255367 a:= n-> (p-> numtheory[primroot](p)&^(p-2) mod p)(ithprime(n)):
%p A255367 seq(a(n), n=1..70);
%t A255367 a[n_] := With[{p = Prime[n]}, Mod[PrimitiveRoot[p]^(p-2), p]]; Array[a, 70] (* _Jean-François Alcover_, Mar 24 2017 *)
%Y A255367 Cf. A000040, A001918, A254309.
%K A255367 nonn,look
%O A255367 1,2
%A A255367 _Alois P. Heinz_, May 04 2015