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%I #10 Oct 23 2023 15:07:16
%S 1,1,1,1,3,1,1,1,1,3,5,1,3,1,3,1,7,1,1,3,1,5,9,1,9,3,1,1,5,3,11,1,5,7,
%T 3,1,3,1,3,3,13,1,7,5,3,9,15,1,1,9,7,3,1,1,15,1,1,5,17,3,9,11,1,1,9,5,
%U 19,7,9,3,5,1,21,3,9,1,5,3,11,3,1,13,23,1,21,7,5,5,3,3,3,9,11,15,3,1,25,1,5,9
%N Fully multiplicative with a(p) = oddpart(primepi(p)).
%H Antti Karttunen, <a href="/A366789/b366789.txt">Table of n, a(n) for n = 1..52711</a>
%H <a href="/index/Pri#prime_indices">Index entries for sequences related to prime indices in the factorization of n</a>
%F a(n) = A000265(A003963(n)).
%t {1}~Join~Array[#/2^IntegerExponent[#, 2] &@ Apply[Times, PrimePi[#1]^#2 & @@@ FactorInteger[#]] &, 120, 2] (* _Michael De Vlieger_, Oct 23 2023 *)
%o (PARI)
%o A000265(n) = (n>>valuation(n,2));
%o A366789(n) = { my(f=factor(n)); prod(k=1, #f~, A000265(primepi(f[k, 1]))^f[k, 2]); };
%Y Cf. A000265, A000720, A003963, A366790.
%Y Cf. also A336466.
%K nonn,mult
%O 1,5
%A _Antti Karttunen_, Oct 23 2023
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