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 A092523 #16 Feb 16 2025 08:32:52
%S A092523 0,1,1,1,1,1,1,2,1,1,2,1,1,1,1,1,2,2,1,2,1,1,2,1,1,2,1,2,2,1,1,2,2,1,
%T A092523 2,1,1,2,2,1,1,1,2,2,1,2,2,2,1,2,1,1,3,1,1,2,1,2,2,2,1,2,1,1,2,1,2,2,
%U A092523 1,1,2,2,2,2,1,1,2,2,1,2,2,1,3,1,1,2,1,2,2,1,1,2,2,2,2,1,1,3,1,1,2,2
%N A092523 Number of distinct prime factors of n-th odd number.
%H A092523 Ray Chandler, <a href="/A092523/b092523.txt">Table of n, a(n) for n = 1..10000</a>
%H A092523 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/DistinctPrimeFactors.html">Distinct Prime Factors</a>.
%H A092523 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/OddNumber.html">Odd Number</a>.
%F A092523 a(n) = A001221(2*n-1).
%F A092523 Sum_{k=1..n} a(k) = n * (log(log(n)) + B - 1/2) + O(n/log(n)), where B is Mertens's constant (A077761). - _Amiram Eldar_, Sep 21 2024
%t A092523 Table[PrimeNu[n],{n,1,211,2}] (* _Harvey P. Dale_, May 25 2015 *)
%o A092523 (PARI) a(n) = omega(2*n-1); \\ _Amiram Eldar_, Sep 21 2024
%Y A092523 Cf. A001221, A077761, A091304, A099812.
%K A092523 nonn,easy
%O A092523 1,8
%A A092523 _Reinhard Zumkeller_, Apr 07 2004