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 A377864 #16 Nov 21 2024 09:06:20
%S A377864 1,1,1,1,3,1,1,3,1,1,3,1,5,3,1,1,3,5,1,3,1,1,5,1,7,3,1,5,3,1,1,7,5,1,
%T A377864 3,1,1,5,7,1,9,1,5,3,1,7,3,5,1,9,1,1,7,1,1,3,1,5,9,7,11,3,5,1,3,1,7,9,
%U A377864 1,1,3,11,5,7,1,1,9,5,1,3,7,1,11,1,13,9
%N A377864 Largest divisor of 2n-1 less than or equal to sqrt(2n-1).
%F A377864 a(n) = A033676(2n-1).
%F A377864 a(n) = A377499(n) - A219695(n).
%t A377864 a[n_]:=Module[{k=2n-1},While[!Divisible[2n-1,k] || k>Sqrt[2n-1] ,k--]; k]; Array[a,86] (* _Stefano Spezia_, Nov 17 2024 *)
%o A377864 (PARI) a(n) = {my(d = divisors(2*n-1)); d[ceil(#d/2)]} \\ _Thomas Scheuerle_, Nov 17 2024
%Y A377864 Odd bisection of A033676.
%Y A377864 Cf. A377499, A219695.
%K A377864 nonn,easy
%O A377864 1,5
%A A377864 _Charles Kusniec_, Nov 10 2024