cp's OEIS Frontend

A325225 Lesser of the number of prime factors of n counted with multiplicity and the maximum prime index of n.

%I A325225 #10 Apr 19 2019 11:22:09
%S A325225 0,1,1,1,1,2,1,1,2,2,1,2,1,2,2,1,1,2,1,3,2,2,1,2,2,2,2,3,1,3,1,1,2,2,
%T A325225 2,2,1,2,2,3,1,3,1,3,3,2,1,2,2,3,2,3,1,2,2,4,2,2,1,3,1,2,3,1,2,3,1,3,
%U A325225 2,3,1,2,1,2,3,3,2,3,1,3,2,2,1,4,2,2,2,4,1,3,2,3,2,2,2,2,1,3,3,3,1,3,1,4,3
%N A325225 Lesser of the number of prime factors of n counted with multiplicity and the maximum prime index of n.
%C A325225 A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798.
%H A325225 Antti Karttunen, <a href="/A325225/b325225.txt">Table of n, a(n) for n = 1..65537</a>
%H A325225 FindStat, <a href="http://www.findstat.org/StatisticsDatabase/St000533">St000533: The maximal number of non-attacking rooks on a Ferrers shape</a>
%F A325225 a(n) = min(A001222(n), A061395(n)).
%e A325225 88 has 4 prime indices {1,1,1,5}, the maximum of which is 5, so a(88) = min(4,5) = 4.
%t A325225 Table[Min[PrimeOmega[n],PrimePi[FactorInteger[n][[-1,1]]]],{n,100}]
%o A325225 (PARI)
%o A325225 A061395(n) = if(1==n, 0, primepi(vecmax(factor(n)[, 1])));
%o A325225 A325225(n) = min(bigomega(n), A061395(n)); \\ _Antti Karttunen_, Apr 14 2019
%Y A325225 Positions of 1's are A174090. Positions of 2's are A325229.
%Y A325225 Cf. A001222, A056239, A061395, A065770, A093641, A112798, A252464, A257541, A257990, A263297, A325169, A325224, A325227, A325232.
%K A325225 nonn,hear
%O A325225 1,6
%A A325225 _Gus Wiseman_, Apr 12 2019
%E A325225 More terms from _Antti Karttunen_, Apr 14 2019