A324388 - OEIS

%I #7 Feb 28 2019 18:54:33

%S 1,2,3,4,5,3,7,8,9,5,11,4,13,7,5,16,17,9,19,5,7,11,23,8,25,13,27,7,29,

%T 15,31,32,11,17,7,9,37,19,13,8,41,21,43,11,9,23,47,16,49,25,17,13,53,

%U 27,11,8,19,29,59,20,61,31,9,64,13,33,67,17,23,35,71,9,73,37,25,19,11,39,79,16,81,41,83,28,17,43,29,11,89,45

%N If n is a prime power (in A000961), then a(n) = n, otherwise a(n) is the greatest proper unitary divisor of n.

%H Antti Karttunen, <a href="/A324388/b324388.txt">Table of n, a(n) for n = 1..20000</a>

%o (PARI) A324388(n) = if(1>=omega(n),n,fordiv(n,d,if((d>1)&&(1==gcd(d,n/d)),return(n/d))));

%Y Cf. A000961, A306264.

%K nonn

%O 1,2

%A _Antti Karttunen_ and _David James Sycamore_, Feb 28 2019