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 A349049 #19 Jun 27 2025 15:30:08
%S A349049 0,1,2,3,4,3,4,5,7,7,8,8,9,9,9,10,11,10,11,10,9,9,10,11,13,13,15,15,
%T A349049 16,16,17,18,17,17,17,17,18,18,18,18,19,18,19,20,20,20,21,21,23,23,23,
%U A349049 23,24,23,23,23,23,23,24,24,25,25,24,25,25,24,25,25,26,26,27,28,29,29,29,29,28
%N A349049 Number of prime factors (with multiplicity) of the denominator of the harmonic number H(n) = Sum_{k=1..n} 1/k.
%F A349049 a(n) = A001222(A002805(n)).
%o A349049 (SageMath) [sloane.A001222(A002805(n)) for n in range(1, 78)]
%o A349049 (PARI) my(h=0); for(n=1,77,h+=1/n;print1(bigomega(denominator(h)),", ")); \\ _Joerg Arndt_, Nov 07 2021
%o A349049 (Python)
%o A349049 from sympy import harmonic, factorint
%o A349049 def a(n): return sum(factorint(harmonic(n).denominator).values())
%o A349049 print([a(n) for n in range(1, 78)]) # _Michael S. Branicky_, Nov 07 2021
%Y A349049 Cf. A001222, A002805, A308967.
%K A349049 nonn
%O A349049 1,3
%A A349049 _Kam Kong_, Nov 07 2021