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 A358434 #55 Apr 06 2023 13:00:17
%S A358434 1,1,0,0,0,1,0,0,1,0,0,1,0,0,2,0,0,1,0,1,0,0,0,0,1,0,0,1,0,1,0,0,0,0,
%T A358434 2,0,0,0,0,1,0,1,0,0,2,0,0,0,1,1,0,0,0,1,0,1,0,0,0,0,0,0,2,0,0,1,0,0,
%U A358434 0,1,0,1,0,0,0,0,2,0,0,0,1,0,0,1,0,0,0,1,0,1,2,0,0,0,0,0,0,1,2,0,0,0,0,1,0
%N A358434 Number of odd middle divisors of n, where "middle divisor" means a divisor in the half-open interval [sqrt(n/2), sqrt(n*2)).
%C A358434 Number of odd divisors of n in the half-open interval [sqrt(n/2), sqrt(n*2)).
%C A358434 Also number of odd numbers in the n-th row of A299761.
%F A358434 a(n) = A067742(n) - A361561(n). - _Omar E. Pol_, Mar 31 2023
%e A358434 For n = 8 the middle divisor of 8 is [2]. There are no odd middle divisors of 8 so a(8) = 0.
%e A358434 For n = 12 the middle divisors of 12 are [3, 4]. There is only one odd middle divisor of 12 so a(12) = 1.
%e A358434 For n = 15 the middle divisors of 15 are [3, 5]. There are two odd middle divisors of 15 so a(15) = 2.
%t A358434 Table[DivisorSum[n, 1 &, And[OddQ[#], Sqrt[n/2] <= # < Sqrt[2*n]] &], {n, 120}] (* _Michael De Vlieger_, Mar 31 2023 *)
%o A358434 (PARI) a(n) = #select(x->((x >= sqrt(n/2)) && (x < sqrt(n*2)) && x%2), divisors(n)); \\ _Michel Marcus_, Mar 26 2023
%Y A358434 Cf. A001227, A067742, A071090, A071562, A299761, A361561.
%K A358434 nonn
%O A358434 1,15
%A A358434 _Omar E. Pol_, Mar 14 2023