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 A034973 #22 Jul 22 2022 16:43:46
%S A034973 0,1,1,2,2,2,2,3,3,3,4,4,4,4,4,5,5,5,5,5,6,6,6,6,6,6,6,6,7,7,7,8,8,8,
%T A034973 9,9,9,9,10,10,10,10,10,10,9,9,10,10,10,10,10,10,10,10,12,12,13,13,12,
%U A034973 12,12,12,12,13,14,14,14,14,14,14,14,14,14,14,15,15,14,14,15,15,15,15,16
%N A034973 Number of distinct prime factors in central binomial coefficients C(n, floor(n/2)), the terms of A001405.
%C A034973 Sequence is not monotonic. E.g., a(44)=10, a(45)=9 and a(46)=10. The number of prime factors of n! is pi(n), but these numbers are lower.
%C A034973 Prime factors are counted without multiplicity. - _Harvey P. Dale_, May 20 2012
%H A034973 T. D. Noe, <a href="/A034973/b034973.txt">Table of n, a(n) for n = 1..10000</a>
%e A034973 a(25) = omega(binomial(25,12)) = omega(5200300) = 6 because the prime factors are 2, 5, 7, 17, 19, 23.
%t A034973 Table[PrimeNu[Binomial[n,Floor[n/2]]],{n,90}] (* _Harvey P. Dale_, May 20 2012 *)
%o A034973 (PARI) a(n)=omega(binomial(n,n\2)) \\ _Charles R Greathouse IV_, Apr 29 2015
%Y A034973 Cf. A001405, A034974, A067434.
%K A034973 nonn,easy,nice
%O A034973 1,4
%A A034973 _Labos Elemer_