cp's OEIS Frontend

A366785 Greatest common divisor of the number of prime factors (counted with multiplicity, A001222) and the greatest prime index (A061395) of n.

%I A366785 #11 Oct 23 2023 15:17:40
%S A366785 0,1,1,1,1,2,1,1,2,1,1,1,1,2,1,1,1,1,1,3,2,1,1,2,1,2,1,1,1,3,1,1,1,1,
%T A366785 2,2,1,2,2,1,1,1,1,1,3,1,1,1,2,3,1,3,1,2,1,4,2,2,1,1,1,1,1,1,2,1,1,1,
%U A366785 1,1,1,1,1,2,3,1,1,3,1,1,2,1,1,4,1,2,2,1,1,1,2,3,1,1,2,2,1,1,1,1,1,1,1,2,1
%N A366785 Greatest common divisor of the number of prime factors (counted with multiplicity, A001222) and the greatest prime index (A061395) of n.
%H A366785 Antti Karttunen, <a href="/A366785/b366785.txt">Table of n, a(n) for n = 1..65537</a>
%H A366785 <a href="/index/Pri#prime_indices">Index entries for sequences related to prime indices in the factorization of n</a>
%F A366785 a(n) = gcd(A001222(n), A061395(n)).
%F A366785 For n >= 2, a(n) = A001222(n) / A360615(n) = A061395(n) / A360614(n).
%o A366785 (PARI)
%o A366785 A061395(n) = if(n>1, primepi(vecmax(factor(n)[, 1])), 0);
%o A366785 A366785(n) = gcd(bigomega(n), A061395(n));
%Y A366785 Cf. A001222, A061395, A340608 (positions of 1's), A360614, A360615.
%K A366785 nonn
%O A366785 1,6
%A A366785 _Antti Karttunen_, Oct 23 2023