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 A193348 #22 Aug 12 2024 04:22:42
%S A193348 1,1,1,2,1,1,1,1,2,1,1,2,1,1,1,2,1,2,1,2,1,1,1,1,2,1,1,2,1,1,1,2,1,1,
%T A193348 1,3,1,1,1,1,1,1,1,2,2,1,1,2,2,2,1,2,1,1,1,1,1,1,1,2,1,1,2,2,1,1,1,2,
%U A193348 1,1,1,2,1,1,2,2,1,1,1,2,2,1,1,2,1,1,1,1,1,2,1,2,1,1,1,2,1,2,2,3
%N A193348 Number of odd divisors of tau(n).
%H A193348 Reinhard Zumkeller, <a href="/A193348/b193348.txt">Table of n, a(n) for n = 1..10000</a>
%F A193348 a(n) = A001227(A000005(n)). - _Reinhard Zumkeller_, Jul 25 2011
%F A193348 From _Amiram Eldar_, Aug 12 2024: (Start)
%F A193348 a(n) = 1 if and only if n is in A036537.
%F A193348 a(n) = A010553(n) if and only if n is a square. (End)
%e A193348 a(36) = 3 because tau(36) = 9 and the 3 odd divisors are {1, 3, 9}.
%t A193348 a[n_] := Block[{d = Divisors[DivisorSigma[0,n]]}, Count[OddQ[d], True]]; Table[a[n], {n, 80}]
%o A193348 (PARI) a(n)=sumdiv(sigma(n,0),d,d%2);
%o A193348 (PARI) a(n)=n=numdiv(n);numdiv(n>>valuation(n,2)) \\ _Charles R Greathouse IV_, Jul 30 2011
%Y A193348 Cf. A000005, A001227, A010553, A036537, A193349.
%K A193348 nonn,easy
%O A193348 1,4
%A A193348 _Michel Lagneau_, Jul 23 2011