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 A332547 #17 Jul 16 2024 14:30:33
%S A332547 1,1,1,1,3,3,1,3,5,5,3,3,7,7,5,1,9,9,5,15,11,11,3,15,13,13,21,7,15,15,
%T A332547 1,11,17,17,21,9,19,19,15,5,21,21,11,33,23,23,3,21,35,25,39,13,27,45,
%U A332547 35,21,29,29,15,15,31,31,21,13,55,33,17,51,35,35
%N A332547 a(n) = largest odd divisor d < n of n*(n+1)/2.
%C A332547 Used by _Michael J. Collins_ in the analysis of A082183 and A082184.
%H A332547 Hugo Pfoertner, <a href="/A332547/b332547.txt">Table of n, a(n) for n = 1..10000</a>
%t A332547 Join[{1},Table[Select[Divisors[(n(n+1))/2],OddQ[#]&&#<n&]//Max,{n,2,80}]] (* _Harvey P. Dale_, Jul 16 2024 *)
%Y A332547 Cf. A000217, A068194 (where a(n)=1), A082183, A082184, A332548, A332549 (where a(n)=3).
%K A332547 nonn
%O A332547 1,5
%A A332547 _N. J. A. Sloane_, Feb 21 2020