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 A357984 #9 Oct 04 2024 08:51:12
%S A357984 1,0,1,0,2,0,2,0,1,0,3,0,3,0,2,0,4,0,4,0,2,0,4,0,4,0,1,0,4,0,5,0,3,0,
%T A357984 4,0,5,0,3,0,6,0,6,0,2,0,6,0,4,0,4,0,6,0,6,0,4,0,7,0,7,0,2,0,6,0,8,0,
%U A357984 4,0,8,0,8,0,4,0,6,0,8,0,1,0,9,0,8,0,4
%N A357984 Replace prime(k) with A000720(k) in the prime factorization of n.
%e A357984 We have 91 = prime(4) * prime(6), so a(91) = pi(4) * pi(6) = 6.
%t A357984 primeMS[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
%t A357984 Table[Times@@PrimePi/@primeMS[n],{n,100}]
%Y A357984 Other multiplicative sequences: A003961, A357852, A064988, A064989, A357983.
%Y A357984 The version for p instead of pi is A299200, horz A357977, strict A357982.
%Y A357984 The version for nu is A355741.
%Y A357984 The version for bigomega is A355742.
%Y A357984 The horizontal version is A357980.
%Y A357984 A000040 lists the prime numbers.
%Y A357984 A000720 is PrimePi.
%Y A357984 A056239 adds up prime indices, row-sums of A112798.
%Y A357984 Cf. A033879, A033880, A063834, A066207, A076610, A296150, A357975.
%K A357984 nonn,mult
%O A357984 1,5
%A A357984 _Gus Wiseman_, Oct 25 2022