A211243 Order of 7 mod n-th prime: least k such that prime(n) divides 7^k-1.

1, 1, 4, 0, 10, 12, 16, 3, 22, 7, 15, 9, 40, 6, 23, 26, 29, 60, 66, 70, 24, 78, 41, 88, 96, 100, 51, 106, 27, 14, 126, 65, 68, 69, 74, 150, 52, 162, 83, 172, 178, 12, 10, 24, 98, 99, 210, 37, 113, 228, 116, 238, 240, 125, 256, 262, 268, 135, 138, 20, 141, 292

Offset

1,3

Links

T. D. Noe, Table of n, a(n) for n = 1..1000

Mathematica

nn = 7; 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(7, A000040[n])); # Muniru A Asiru, Feb 06 2019
(PARI) a(n, {base=7}) = my(p=prime(n)); if(base%p, znorder(Mod(base, p)), 0) \\ Jianing Song, May 13 2024

Crossrefs

Cf. A019337 (full reptend primes in base 7).

In other bases: A014664, A062117, A082654, A211241, A211242, A211244, A211245, A002371.

Row lengths of A201911. - Michel Marcus, Feb 04 2019

Sequence in context: A293933 A345057 A158976 * A181626 A279432 A019127

Adjacent sequences: A211240 A211241 A211242 * A211244 A211245 A211246

Keyword

nonn,easy

Author

T. D. Noe, Apr 11 2012

Status

approved