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A373370 a(n) = gcd(bigomega(n), A064097(n)), where bigomega is number of prime factors with repetition, and A064097 is a quasi-logarithm defined inductively by a(1) = 0 and a(p) = 1 + a(p-1) if p is prime and a(n*m) = a(n) + a(m) if m,n > 1. 3

%I #7 Jun 05 2024 19:23:05

%S 0,1,1,2,1,1,1,3,2,2,1,1,1,1,1,4,1,1,1,1,2,2,1,1,2,2,3,3,1,3,1,5,1,2,

%T 1,2,1,1,1,2,1,1,1,1,1,2,1,1,2,1,1,1,1,1,2,1,2,2,1,1,1,2,1,6,2,1,1,1,

%U 1,1,1,1,1,2,1,1,1,1,1,1,4,2,1,4,2,1,1,4,1,4,1,3,1,2,1,1,1,3,3,4,1,1,1,4,3

%N a(n) = gcd(bigomega(n), A064097(n)), where bigomega is number of prime factors with repetition, and A064097 is a quasi-logarithm defined inductively by a(1) = 0 and a(p) = 1 + a(p-1) if p is prime and a(n*m) = a(n) + a(m) if m,n > 1.

%C As A001222 and A064097 are both fully additive sequences, all sequences that give the positions of multiples of some natural number k in this sequence are closed under multiplication, i.e., are multiplicative semigroups.

%H Antti Karttunen, <a href="/A373370/b373370.txt">Table of n, a(n) for n = 1..100000</a>

%o (PARI)

%o A064097(n) = if(1==n,0,1+A064097(n-(n/vecmin(factor(n)[,1]))));

%o A373370(n) = gcd(bigomega(n), A064097(n));

%Y Cf. A001222, A064097.

%Y Cf. also A373365, A373366.

%K nonn

%O 1,4

%A _Antti Karttunen_, Jun 05 2024

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Last modified June 29 18:05 EDT 2024. Contains 373855 sequences. (Running on oeis4.)