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%I #31 Sep 01 2018 17:44:44
%S 4,6,33,335,355,3073,8408,64690,481044,1304693,1304719,3524318,
%T 3524654,9559785,9559905,70115803,189963234,189963918,514278263,
%U 1394194660,3779856591,10246935974,75370122456,204475052725,204475053325,1505578023783,1505578024917
%N Numbers n divisible by pi(n) [A057809] with prime pi(n); i.e., largest prime factor of n equals pi(n).
%H Giovanni Resta, <a href="/A071394/b071394.txt">Table of n, a(n) for n = 1..49</a>
%F A000720(a(n)) = A006530(a(n)) = A256394(n). - _Jonathan Sondow_, Apr 15 2015
%e pi(8408) = 1051 and 8408 = 2*2*2*1051.
%t c = 0; lpf[n_] := If[ PrimeQ[n], c++; n, Transpose[ FactorInteger[n]][[1, -1]]]; Do[ If[ lpf[n] == c, Print[n]], {n, 2, 10^7}]
%t Select[Select[Range[2,10^6],IntegerQ[#/PrimePi[#]]&],PrimeQ[PrimePi[#]]&] (* _Ivan N. Ianakiev_, Apr 15 2015 *)
%t Select[Range[10^6], FactorInteger[#][[-1, 1]] == PrimePi@ # &] (* _Michael De Vlieger_, Jul 30 2017 *)
%o (PARI) isok(n) = isprime(p=primepi(n)) && !(n % p); \\ _Michel Marcus_, Jul 31 2017
%Y Cf. A000720, A006530, A256394.
%K nonn
%O 1,1
%A _Jason Earls_, Jun 12 2002
%E Edited and extended by _Robert G. Wilson v_, Jun 13 2002
%E More terms from _Hans Havermann_, Jul 02 2002
%E a(26)-a(27) from _Giovanni Resta_, Mar 28 2017
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