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 A216829 #37 Apr 23 2025 17:37:15
%S A216829 1,3,2,3,9,5,6,6,4,9,3,11,10,27,14,5,15,6,18,6,10,7,18,23,21,12,26,10,
%T A216829 9,29,30,9,6,33,33,35,9,30,15,39,81,41,4,42,11,6,15,18,24,45,50,51,6,
%U A216829 53,18,18,14,22,18,12,55,30,50,7,21,65,9,54,34,69,69
%N A216829 2*a(n) is the multiplicative order of 2 mod 3*(2n-1).
%C A216829 2*a(n) is the smallest m such that 3*(2n-1) | (2^m+1).
%C A216829 a(n) is the least k such that 2*n-1 is a factor of A002450(k). - _Ali Sada_, Apr 02 2025
%H A216829 Muniru A Asiru, <a href="/A216829/b216829.txt">Table of n, a(n) for n = 1..10000</a>
%F A216829 a(n) = A216833(n)/2.
%t A216829 Table[MultiplicativeOrder[2, 3*(2*n-1)], {n, 100}]/2 (* _T. D. Noe_, Sep 19 2012 *)
%o A216829 (PARI) vector(100,n,znorder(Mod(2,3*(2*n-1)))/2) \\ _Joerg Arndt_, Sep 14 2012.
%o A216829 (GAP) List([1..70],n->OrderMod(2,3*(2*n-1))/2); # _Muniru A Asiru_, Feb 26 2019
%Y A216829 Cf. A003558, A002326, A216469, A216833, A002450.
%K A216829 nonn
%O A216829 1,2
%A A216829 _V. Raman_, Sep 17 2012