cp's OEIS Frontend

A094593 a(n) = (p-1)/x, where p = prime(n) and x = ord(3,p), the smallest positive integer such that 3^x == 1 mod p.

%I A094593 #17 Jan 16 2020 01:00:46
%S A094593 1,1,2,4,1,1,2,1,1,2,5,1,2,1,2,6,3,2,6,1,2,1,2,1,3,2,4,1,1,2,1,1,1,3,
%T A094593 2,1,2,1,2,4,2,12,1,1,1,1,2,4,1,2,2,2,1,2,1,9,4,1,1,1,9,2,8,1,1,2,2,2,
%U A094593 1,2,3,2,1,2,1,2,1,2,2,4,10,16,3,2,1,2
%N A094593 a(n) = (p-1)/x, where p = prime(n) and x = ord(3,p), the smallest positive integer such that 3^x == 1 mod p.
%H A094593 T. D. Noe, <a href="/A094593/b094593.txt">Table of n, a(n) for n = 3..1000</a>
%F A094593 a(n) = (A000040(n)-1)/A062117(n).
%o A094593 (PARI) a(n)=(prime(n)-1)/if(n<0,0,k=1;while((3^k-1)%prime(n)>0,k++);k)
%o A094593 (Python)
%o A094593 from sympy import prime, n_order
%o A094593 def A094593(n):
%o A094593     p = prime(n)
%o A094593     return 1 if n == 3 else (p-1)//n_order(3,p) # _Chai Wah Wu_, Jan 15 2020
%Y A094593 Cf. A001917.
%K A094593 nonn
%O A094593 3,3
%A A094593 _Benoit Cloitre_, Jun 06 2004