A380482 a(n) is the multiplicative order of -3 modulo prime(n); a(2) = 0 for completion.

1, 0, 4, 3, 10, 6, 16, 9, 22, 28, 15, 9, 8, 21, 46, 52, 58, 5, 11, 70, 12, 39, 82, 88, 48, 100, 17, 106, 54, 112, 63, 130, 136, 69, 148, 25, 39, 81, 166, 172, 178, 90, 190, 16, 196, 99, 105, 111, 226, 114, 232, 238, 120, 250, 256, 262, 268, 15, 138, 280

Offset

1,3

Links

Jianing Song, Table of n, a(n) for n = 1..10000

Mathematica

A380482[n_] := If[n == 2, 0, MultiplicativeOrder[-3, Prime[n]]];
Array[A380482, 100] (* Paolo Xausa, Jun 29 2025 *)

Prog

(PARI) a(n, {k=-3}) = my(p = prime(n)); if(k%p==0, 0, znorder(Mod(k, p)))

Crossrefs

Cf. A105875 (primes having primitive root -3).

Cf. bases 2..10: A014664, A062117, A082654, A211241, A211242, A211243, A211244, A211245, A002371.

Cf. bases -2..-10: A337878 (if first term 1), this sequence, A380531, A380532, A380533, A380540, A380541, A380542, A385222.

Sequence in context: A242531 A275160 A363469 * A369710 A147756 A213768

Adjacent sequences: A380479 A380480 A380481 * A380483 A380484 A380485

Keyword

nonn,easy

Author

Jianing Song, Jun 27 2025

Status

approved