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 A143665 #20 Dec 28 2024 16:19:12
%S A143665 2,3,31,13,11,7,19531,313,19,521,12207031,601,305175781,29,181,17,409,
%T A143665 5167,191,41,379,23,8971,390001,101,5227,109,234750601,59,61,1861,
%U A143665 2593,199,3061,211,37,149,761,79,241,2238236249,43,1644512641,89,1171,47
%N A143665 a(n) is the least prime such that the multiplicative order of 5 mod a(n) equals n.
%H A143665 Max Alekseyev, <a href="/A143665/b143665.txt">Table of n, a(n) for n = 1..520</a>
%t A143665 p = 2; t = Table[0, {100}]; While[p < 3000000001, a = MultiplicativeOrder[5, p]; If[0 < a < 101 && t[[a]] == 0, t[[a]] = p]; p = NextPrime@ p]; t (* _Robert G. Wilson v_, Oct 13 2014 *)
%Y A143665 Cf. A064081, A218357.
%Y A143665 Cf. A112927 (base 2), A143663 (base 3), A112092 (base 4), A143665 (base 5), A379639 (base 6), A379640 (base 7), A379641 (base 8), A379642 (base 9), A007138 (base 10), A379644 (base 11), A252170 (base 12).
%K A143665 nonn
%O A143665 1,1
%A A143665 _Vladimir Shevelev_, Aug 28 2008
%E A143665 a(23)-a(40) from _Robert G. Wilson v_, Oct 13 2014
%E A143665 a(41)-a(46) from _Robert G. Wilson v_, Oct 15 2014