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

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, 102, 53, 54, 112, 126, 65, 136, 138, 148, 150, 3, 162, 83, 172, 89, 90, 95, 24, 196, 66, 14, 222, 113, 114, 8, 119, 120, 125, 256, 131, 268, 54, 138, 280

Offset: 1

Author

Eric Chen, Nov 15 2014

Keywords

• nonn
• base

Comments

For p >= 5 (n >= 3): multiplicative order of 12 mod prime(n). - Joerg Arndt, Nov 15 2014

Examples

			For n=9, prime(9) = 23, 1/23 in base 12 is 0. 06316948421 06316948421 ..., which has period 11, so a(9) = 11.
		

Links

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

Crossrefs

Cf. A002371 (decimal versions).

Programs

Maple

with(numtheory):
a:= n-> `if`(n<3, 0, order(12, ithprime(n))):
seq(a(n), n=1..100);  # Alois P. Heinz, Nov 16 2014

PARI

/* nonzero terms only: */
forprime(p=5,10^3,print1(znorder(Mod(12,p)),", ")); \\ Joerg Arndt, Nov 15 2014

Formula

a(n) = A246004(prime(n)).