|
%I #14 Apr 23 2022 05:36:03
%S 30,182,195,399,870,1023,1406,1443,1722,2915,3782,4623,5402,7055,8099,
%T 10302,10815,11990,12099,12882,12995,16383,17423,18906,19599,24806,
%U 24963,26895,30102,32942,33123,37442,37635,39999,44943,52670,52899,54755,63503,66306,66563
%N Squarefree numbers k with largest prime factor = floor(sqrt(k)).
%C If k = p(1)*p(2)*...p(r) is in the sequence, where p(r) is the largest prime factor, then p(1)*p(2)*...*p(r-1) - p(r) = 1 or 2.
%H Amiram Eldar, <a href="/A071311/b071311.txt">Table of n, a(n) for n = 1..10000</a>
%e 1023 = 3*11*31 and sqrt(1023) = 31.98437... hence 1023 is in the sequence.
%t Select[Range[2, 50000], SquareFreeQ[#] && FactorInteger[#][[-1,1]] == Floor[Sqrt[#]] &] (* _Amiram Eldar_, Apr 23 2022 *)
%o (PARI) for(n=2,100000,if(issquarefree(n)*component(component(factor(n),1),omega(n))==floor(sqrt(n)),print1(n,",")))
%Y Intersection of A005117 and A071835.
%K easy,nonn
%O 1,1
%A _Benoit Cloitre_, Jun 11 2002
|
