This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A385222 #18 Jul 07 2025 10:44:10
%S A385222 0,2,0,3,1,3,16,9,11,28,30,6,10,42,23,26,29,60,66,70,8,26,82,44,96,4,
%T A385222 17,106,108,112,21,65,8,23,148,150,39,162,83,86,89,180,190,192,49,198,
%U A385222 15,111,226,228,232,14,15,25,256,131,268,10,138,28
%N A385222 a(n) is the multiplicative order of -10 modulo prime(n); a(1) = a(3) = 0 for completion.
%H A385222 Jianing Song, <a href="/A385222/b385222.txt">Table of n, a(n) for n = 1..10000</a>
%t A385222 A385222[n_] := If[n == 1 || n == 3, 0, MultiplicativeOrder[-10, Prime[n]]];
%t A385222 Array[A385222, 100] (* _Paolo Xausa_, Jun 29 2025 *)
%o A385222 (PARI) a(n,{k=-10}) = my(p = prime(n)); if(k%p==0, 0, znorder(Mod(k,p)))
%Y A385222 Cf. A007348 (primes having primitive root -10).
%Y A385222 Cf. bases 2..10: A014664, A062117, A082654, A211241, A211242, A211243, A211244, A211245, A002371.
%Y A385222 Cf. bases -2..-10: A337878 (if first term 1), A380482, A380531, A380532, A380533, A380540, A380541, A380542, this sequence.
%K A385222 nonn,easy
%O A385222 1,2
%A A385222 _Jianing Song_, Jun 27 2025