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A246489 Duodecimal period of 1/(n-th prime) (0 by convention for the primes 2 and 3).

%I A246489 #22 Nov 19 2023 21:16:12
%S A246489 0,0,4,6,1,2,16,6,11,4,30,9,40,42,23,52,29,15,66,35,36,26,41,8,16,100,
%T A246489 102,53,54,112,126,65,136,138,148,150,3,162,83,172,89,90,95,24,196,66,
%U A246489 14,222,113,114,8,119,120,125,256,131,268,54,138,280
%N A246489 Duodecimal period of 1/(n-th prime) (0 by convention for the primes 2 and 3).
%C A246489 For p >= 5 (n >= 3): multiplicative order of 12 mod prime(n). - _Joerg Arndt_, Nov 15 2014
%H A246489 Alois P. Heinz, <a href="/A246489/b246489.txt">Table of n, a(n) for n = 1..10000</a>
%F A246489 a(n) = A246004(prime(n)).
%e A246489 For n=9, prime(9) = 23, 1/23 in base 12 is 0. 06316948421 06316948421 ..., which has period 11, so a(9) = 11.
%p A246489 with(numtheory):
%p A246489 a:= n-> `if`(n<3, 0, order(12, ithprime(n))):
%p A246489 seq(a(n), n=1..100);  # _Alois P. Heinz_, Nov 16 2014
%o A246489 (PARI) /* nonzero terms only: */
%o A246489 forprime(p=5,10^3,print1(znorder(Mod(12,p)),", ")); \\ _Joerg Arndt_, Nov 15 2014
%Y A246489 Cf. A002371 (decimal versions).
%K A246489 nonn,base
%O A246489 1,3
%A A246489 _Eric Chen_, Nov 15 2014