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A211244
Order of 8 mod n-th prime: least k such that prime(n) divides 8^k-1.
12
0, 2, 4, 1, 10, 4, 8, 6, 11, 28, 5, 12, 20, 14, 23, 52, 58, 20, 22, 35, 3, 13, 82, 11, 16, 100, 17, 106, 12, 28, 7, 130, 68, 46, 148, 5, 52, 54, 83, 172, 178, 60, 95, 32, 196, 33, 70, 37, 226, 76, 29, 119, 8, 50, 16, 131, 268, 45, 92, 70, 94, 292, 34, 155, 52
OFFSET
1,2
FORMULA
a(n) = A014664(n)/gcd(3, A014664(n)). - Jianing Song, May 13 2024
MATHEMATICA
nn = 8; Table[If[Mod[nn, p] == 0, 0, MultiplicativeOrder[nn, p]], {p, Prime[Range[100]]}]
PROG
(GAP) A000040:=Filtered([1..350], IsPrime);;
List([1..Length(A000040)], n->OrderMod(8, A000040[n])); # Muniru A Asiru, Feb 06 2019
(PARI) a(n, {base=8}) = my(p=prime(n)); if(base%p, znorder(Mod(base, p)), 0) \\ Jianing Song, May 13 2024
CROSSREFS
Cf. A053451 (order of 8 mod 2n+1), A019338 (full reptend primes in base 8).
Sequence in context: A102405 A363575 A271206 * A228337 A114506 A114848
KEYWORD
nonn,easy
AUTHOR
T. D. Noe, Apr 11 2012
STATUS
approved