A246489 - OEIS

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

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OFFSET

1,3

COMMENTS

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

LINKS

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

FORMULA

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

EXAMPLE

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

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

PROG

(PARI) /* nonzero terms only: */

forprime(p=5, 10^3, print1(znorder(Mod(12, p)), ", ")); \\ Joerg Arndt, Nov 15 2014

CROSSREFS

Cf. A002371 (decimal versions).

Sequence in context: A106144 A154478 A255695 * A343624 A309445 A051261

Adjacent sequences: A246486 A246487 A246488 * A246490 A246491 A246492

KEYWORD

nonn,base

AUTHOR

Eric Chen, Nov 15 2014

STATUS

approved