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 A385231 #21 Jun 30 2025 04:39:27 %S A385231 1,1,3,11,7,21,23,15,11,41,51,53,21,27,83,111,113,57,131,141,153,173, %T A385231 87,61,191,105,221,7,231,233,27,251,127,5,261,273,281,293,303,107,323, %U A385231 165,341,175,177,363,371,19,393,205,137,59,431,63,443,453,473,483,491,177,181,551,277,187,141 %N A385231 Odd multiplicative orders of -5 modulo primes. %C A385231 Odd elements in A380532. %C A385231 a(n) is the multiplicative order of -5 modulo A385225(n). %H A385231 Jianing Song, <a href="/A385231/b385231.txt">Table of n, a(n) for n = 1..10000</a> %t A385231 Select[Map[MultiplicativeOrder[-5, #] &, Prime[Range[200]]], OddQ] (* _Paolo Xausa_, Jun 30 2025 *) %o A385231 (PARI) forprime(p=2, 1e4, if(p!=5, z=znorder(Mod(-5, p)); if(z%2, print1(z, ", ")))) %Y A385231 Cf. A380532, A385225 (corresponding primes). %Y A385231 Cf. other bases: A139686 (base 2), A385226 (base 3), A385227 (base 4), A385193 (base 5), A385228 (base -2), A385229 (base -3), A385230 (base -4), this sequence (base -5). %K A385231 nonn,easy %O A385231 1,3 %A A385231 _Jianing Song_, Jun 22 2025